Well, the tl;dr way to summarize what I'm about to type up would be to say that the soil will be enough assuming you've followed sub's recipe to an exact T, including letting it sit for 45-60 days. As long as you follow his instructions, you'll only need to water the soil. No catch!
Gonna be a bit of a lengthy reply so forgive me in advance
Please allow me to explain a little as to how organic soil works exactly in hopes that it will give you a better idea of what's going on with your soil and it's relationship with your plants. Keep in mind that this is based on my limited knowledge and I'm sure someone with more expertise would be able to provide better information.
A typical blend of soil will consist of a base (typically peat or coco), aeration (perlite, pumice, lava rocks, rice hulls, etc), compost (EWC and/or compost), and organic amendments (meals, guanos, minerals, etc). Your soil will have no life without any compost and amendments, without those two components you pretty much just have dirt. Your base (coco or peat) is mostly carbon based where as most of your amendments are nitrogen based. Individually, your peat and your amendments won't be able to do much on their own, however when they're combined they can begin the composting process. This allows the amendments to release their nutrients into the base via decomposition, creating a living soil. The compost that you add to your soil mix provides nutrients and microbes, EWC does this as well.
When you make a soil mix, you're combining a base, aeration, compost, and amendments together into one single medium. By keeping it moist and turning it consistently, you're provided the microbes with the air and water they need to survive. Your amendments (blood meal or guano for example) have their own set of NPK ratios, however the nutrients aren't readily available for the plants to absorb until they've decomposed. This is why people use synthetic nutes, because synthetic nutes are designed to be made available to the plant instantly. So pretty much, the things that will help your amendments decompose come in many shapes and sizes. You have the microbes (fungi and bacteria) which are responsible for munching on the amendments in your soil, they then proceed to excrete the amendments back into the soil. The excrement from these microbes is where your nutrients come from, once your meals/guanos/etc have been devoured by these microbes, the nutrients are excreted out of the microbes and are now available to the plant whenever it feels like eating. There will also be a variety of bugs doing this same process as well, you'll come to see little mites/flies in your soil that are actually good guys. They munch on your decomposing amendments and their excrement is also packed full of nutrients similar to the microbes. Other bugs responsible for this include millipedes, roly polys, soldier flys, and earthworms. All of these microbes and bugs are responsible for providing your plants with the nutrients it needs to survive from start to finish.
That's where your recharge comes in, I happen to use that stuff by the way, it's great! However, recharge doesn't actually load up anything with nutrients. All recharge is is microbes (bacteria and fungi) and a little bit of kelp to keep them alive. Recharge is responsible for recharging the life in your soil, however if you don't have any food for them to munch on they will eventually grow dormant and die off, producing no results. Recharge should be used in conjunction with top dressings. Recharge will essentially jump start the organic process, because it fills your soil with the microbes needed to help decompose the amendments you top dress with.
Another thing to keep in mind is that some things decompose faster than others. Alfalfa meal will begin decomposing pretty much instantly, where as something like blood meal or bone meal can take well over 30 days to fully decompose. Guano will also take near 30 days to fully decompose. This is what people mean when they say your soil is "hot". When people say your soil is "hot", that really means that the soil is decomposing at a rapid rate. When this happens, things literally get hot. Decomposing matter can actually reach temperatures of up to 180 degrees in fact! This is one of the reasons you need to "cook" your soil for a bit, because you don't your roots to be in decomposing soil that's over 100 degrees or they'll get fried! Once the soil is cooked, it's been decomposed. When the soil is cooking, it's decomposing. You want things to be decomposed before you start growing, not decomposing! You'll need to be careful of the compost you use for this exact reason.
The reason I explain all of this is so that you'll know what the reasoning behind the supersoil being enough on it's own without any additional nutes. It's been a while since I've run sub's soil, but from what I can recall, it has two different types of guano, blood meal, bone meals, alfalfa meal, kelp meal, azomite, dolomite lime, and some other stuff that I'm sure I'm forgetting. Not to mention all of the stuff in the bagged soil you purchase for it, I believe he uses 6-8 bags of Roots Organic as his base? Point is, his soil has a TON of stuff in it. Once this soil has finished decomposing, it's some potent stuff for sure. That's why you only want to fill half of your final container with sub's soil, because of how incredibly potent it is! If you were only using bagged soil then you would definitely need to supplement with nutrients somehow. I've yet to come across a bagged soil that will get you through an entire indoor cycle let alone outdoor. They do this on purpose so that you'll need to buy their bottled nute line ups. The supersoil has so much in it though that you don't need to supplement with anything, even for an entire outdoor cycle. All that you need to do is keep the soil alive by providing it with water, if your microbes die then you have nothing to deliver nutrients to your plants. Your soil is literally a living entity. The roots of your plant actually communicate with the microbes living in your soil, when your plant needs a specific nutrient, it signals it's needs to the microbes. The microbes then go to your buffet in the soil, eat their fill, then go back to the roots and defecate readily available nutrients for the roots to immediately absorb. This is why you don't have to do anything, your plant will tell the microbes exactly what it wants and assuming what it wants is in your soil, the microbes will gladly oblige!
I have nothing against Sub or his soil, it's just that there is much better out there in my opinion. Sub's soil served me well when I was using it though, and worked exactly as he claims. It's just that the blood/bone meals and guanos take a long time to decompose and you can get the same nutrients from other sources. I'm running CC's mix now, and if you haven't already made your supersoil I'd recommend looking into CC's mix as it's much better for a variety of reasons. If your supersoil is already made then don't fret, it will still provide you with a quality organic harvest!
CC's mix is just better because it uses a mere 7 amendments, these 7 amendments don't take as long to decompose and they provide you with more conservative doses of the nutrients you need for your plants. Apparently, having too high of a phosphorus content in your soil will provide undesirable conditions for certain microbes. CC also uses Oyster Shell Flour instead of Dolomite Lime. OSF provides calcium just like lime does, and buffers your ph like lime does. The difference between it and lime is that it's more readily available because it doesn't take as long to break down as lime. On top of that, OSF provides your soil with trace elements that lime doesn't. The only amendments CC uses are kelp meal, crab meal, and neem meal. Those three meals have all the NPK your plants could ever need while providing you with extra goodies that blood meal and guanos don't. Crab meal provides a 4-3-0 NPK, but is also responsible for producing a unique microbe called "chitin". Chitin is a predator microbe that will eliminate pretty much any kind of pest you can think of. Chitin devour spider mites and gnats, even their eggs and larvae! Neem meal is similar, provides a 6-4-2 NPK while adding the benefits of neem to your soil for more pest control. Kelp meal has a very modest NPK content, where kelp meal really shines is in the plethora of trace elements it provides your soil. The only catch is that CC's soil requires that you top dress occasionally to keep things going.