It has come to my knowledge that I have retimed every run that I've verified inaccurately. Timing starts when pressing "START". According to the input display in emulators such as FCEUX and Mesen, start is pressed the frame before the screen turns partially or fully black. I am going to retime every run for Calculate A and B, so I can ensure that every run is retimed properly. Apologies for my inaccurate retiming, and I hope all of you understand.
Since my request for mod was accepted I have decided to frame count/retime all of the current runs on the leaderboard due to some being timed inaccurately. As of typing this, I have only retimed the top 10 runs. So if you notice your time is a little different it means it has been retimed properly.