from the looks of your girl at day 40 i think calling it sour sixty is just a advertizing thing. nothing buds in 20 days, which is why most lowryder /diseal/aks dont finish in 60 days either as they start to preflower at day 20ish and need roughly 50 days to pack it on., sour 75-80 perhaps?
Have you bothered in your calculations that I am using a new and different light with these and that could be a factor ?
S_a_H