This actually crossed my mind. Its currently happening @ Nairobi Embassy, F1 is having more interviews than F2B. Been waiting 3 months now since I became current.
Well, decided to be patient and just wait as F2B because Interviews being scheduled now are so close to my dates. Its a tricky situation to be in for sure and as for your case, we will never know for certain the change accelerated your process. Thanks for the info and all the best chasing your dreams in America.