Regarding costs, here in where I live a "regular" person, not one who is classed as "protected" due to disability/age/low income/etc, on a single tariff meter will pay approximately €0.28 per kwh including distribution costs and tax, or $0.33 per kwh. So that's almost $4 per day for a 1kw load on 12/12. People like myself who get the "sociaal tarief", those who are "protected", pay just over half that.
Now, we have no idea what boards he uses, or how many of them. What I do know is that my light pulling a maximum total of 200w on for 12 hours per day comes in at €0.43 per day including distribution costs and taxes, or $0.53 per day, thanks to the missus being classed as so disabled (I'm catching up with her). I don't run it "off peak" because it's in my utility room and we do need to get to the washing machine.
So I can understand where he comes from on electricity prices, running a BFO HID light is out of the question to me even at my tariff as I cannot justify that cost at all, but he has to understand that 12 hours use is 12 hours use whether that is in one block of 12 hours or 12 single hour blocks spread across the day. He MIGHT be able to save by using "off-peak" electricity if it is available with his supply, most are but some are still just a single meter tariff, but ultimately his "cunning plan" is going to cost him a shitload more due to failed grows and his boards lasting well under half as long as they should.
PS. As I was writing this I told the missus what his plan was. Now she knows squat about growing anything under lights, she can grow cherry tomatoes on the window but that's it, and she's finally stopped laughing.