do I have a dwarf?

I've got a couple questions about my grow. I'm new to this...

Basics; I've got 4 Barneys Farm Flower Power AutoFlowers going, pictures taken 27 days after soil break. I transplanted at ~12 days into a Fox Farms Ocean Forest, cut with a little Scotts garden soil, Vermiculite, Perlite, and an organic soil acidifier. Fed them with 6.3pH water and 600ppm nutes (MaxiGrow) at week 2, 3, and 4. Temp and humidity in the space is bang on. 78-84*F lights on, 68-75*F lights off

Currently under 16 23w CFLs with combo of cool and warm with shrouding all around on a 20/4 schedule. Started with the lights at 2-4 inches away, but have recently moved to 6-10 inches due to the other plants getting bigger. (I'm also growing 2 Barneys Farms LSD's, one at 3 weeks the other at 4 weeks) I plan on switching the HPS on in a few weeks for 12/12.

So far all the plants look great in my opinion.

Autos are all fems. My concern is the one FlowerPower plant which is much smaller than the others and appears to have started flowering at about 10 days. That particular auto was the biggest of the 4 until 10 days ago, and now, even my "runt" is taller.

Question, should I be concerned about this single plant? Is it normal to have such a radical difference between plants, supposedly of the same strain? Is it possible this plant will mature sooner but be much smaller?

Also, do you have any other suggestions for me about the grow? I have read nutes are tricky with AF's and I will continue a lite diet for them, and eventually start some MaxiBloom as they develop.

the first 2 pics are of one of the "normal" flower powers (the others look the same) and the rest are of the midget.

They have all been under the same conditions from day one, but yesterday I pulled the midget out and put it under my 150w hps, pretty much just for shits....

thanks all

There can be significant differences among phenotypes within the same strain. I have one "runt" from 3 Big Devil AF's but appears to be catching up, all under a 400w hps. Like yours, the internode spacing is very tight so this may be a growth charaterisitic as well. I think you are on the right track with the 150w HPS, I wouldn't be bashful about getting that light down pretty close (6-8") if the heat is within range. Possibly rotating your other plants daily to the HPS after a week or so might be a option as well.

Thanks for the response. I'm very curious how this thing will react after a week of HPS exposure. I'm keeping an eye on the heat right now, and will probably drop it a little once I get some long term temp readings.
I do plan on having all the autos under HPS once my bigger LSD plants are ready for flower. I have a 400w unit ready, which, teamed with the 150w, should cover all the plants.