SS4 = Sunshine mix number 4 (peatmoss basically, with some lime to buffer ph) and some happy
mycorrhizae.
70-75 days is probably more accurate and i was sometimes chopping before they were perfectly ripe. I basically chopped them at 8 weeks whether they were ready or not, unless i had reason to let them go an extra week. When cultivating for $ time is profit and even if product wasn't 100% ready at 8 weeks it generally was about as heavy as it was going to get and looked as good as it was going to, thus it sold at the same price no matter if it had ripened totally. Also many people like early buds. I also had VERY good genetics (perfect phenotype of a 85% indica OG that grew like crazy) and was trained by professionals that have worked with this DNA and process for years. I wish i had kept my notes, its been years and i was SOOOOO HIGH the entire time all the nuances r a bit fuzzy.
To be honest i am not sure of the specific reason, but i know i was taught to transplant into the final box and then give em 2 weeks under 18/6 to get used to the lights and increased soil space and soil nutes. I also believe that during thiis time i only gave them water, just let them eat the FFOF. I dont think it is for electricity, as the CFL's and T5's are MUCH less electricity even at 24/0. I think it is because the transplant is stressful for the girls and they need a few weeks to get used to it before they start flowering as it is never a good idea to put a stressed plant into flower. Much the same as u want to give em 2 weeks after any major topping/training before flower as they will have to get over the stress.
The pros that taught me didnt use any AN products, i suspect it is because their process could achieve the same results with less expensive products. Just a guess tho. The only thing i do a little different than you is in veg (since i keep the girls in solo cups) they will need some nutes before they reach their flowering home. I use FF grow big. The strain i grew was able to be fed about 4 times straight in the heart of flowering, but this will burn the fuck out of some strains.