I tell all the new racers I help to move the shift lever when it quits pulling hard.
I've seen electric tach not read correctly and be off as much as 1000 RPM when ran with a good mechanical tach in the car
Look at the time slip and write every change down so you can look at the results later away from the track to learn as much as you can from each run and day at the track
My current S/P car picked up 2.4 MPH in the 1/4 mile by raising the shift RPM from 7000 RPM to 7300 RPM at Woodburn in July. It had ran a 8.862 at 148. MPH on the second time trial run, I raised the shift RPM from 7000 RPM to 7300 RPM and the car ran 8.864 ET at 150. MPH on the next time trail run 1 hour later.
I have a three step on the MSD 7AL2 box, the car also has a Biondo 400 box in it to run the throttle stop and shifter, I shift it off of RPM instead of time. It will play back the last run if I hit the line lock button just before I start the run. I've seen a 200 RPM difference on the shift playback from the RPM chips in the three step also
IHTHs