Although @MaynardZed has a valid point, let's ignore that for the argument, I think we'll find that impact as we collect data at the track.
When I look at the data I have from my previous NA car, the shifting that happened in the graph is at 97 mph. If we assume both runs were at the same speed, the version of the data corresponding to the run in which I did not shift gained 2.6 mph during the 0.8 secs it took me to shift. Ignoring the continued speed difference increase after the shift, the data analysis software shows that time gained only during this period was 0.031 secs. If I do manual calculation with approximations and taking average speed during that 0.8 sec time period, I come up with 0.026 secs.
Either way it is not anywhere close to 0.2 secs per shift as @CanAutM3 calculated from his older thread, it is much smaller. Which is the reason I started this thread to see if I am missing something, because I would have believed at face value that "yes, 0.2 per shirt sounds about right." It may not be. Again, how this data will change for the F8x, I do not know, but I am looking forward to finding out
