Speeding up auto and accurate finish times

I have some auto Tangelo Rapido and I was wondering if there is anyway to speed up the already insanely quick finish time? Also, when I see the company info saying 67-70 day flowering time I wonder what variables they use to come to that. 24/0 light? 18/0 light? etc. I know that you can never really know the results until you apply your own variables and get your own conclusive results, but I am in a time crunch and would like to finish in the time advertised. Does anyone else find germ to finish times accurate when you use autos?

ideal conditions and its just a window
small pot start bloom nutes at preflower try and add as little (N) as possible
about all you can do there on the own schedule most auto's take 9-10 weeks in reality