When I was running a 727 you could see the rpm change on the graph when it hit the flash rpm. The rate of rpm gain slowed as the converter started to lock up. You can see a pronounce change on the graph. Running a low first gear set 904 now. There isn’t the pronounced change in rpm gain. It’s a smooth arc now. The low gear set will “show” as a reduction in flash rpm, because the car will move easier/sooner. I have to say logging is very helpful. My logging system is not ideal and you need to figure something’s out, but I can log AFR,throttle position,driveshaft rpm, engine rpm and soon g force with about $600-$700 invested. It’s not plug and play like the high dollar systems, but it is way cheaper.