Fact. Not legal in NHRA as per the rulebook until December 4, 2017.

Is the rulebook wrong?

no, the 1998 NHRA Rule book wasn't wrong, same as the 2018 NHRA Rule book. Manual Starting line controllers have been and continue to be LEGAL in NHRA Pro/Heavy/Sportsman ET bracket racing for over 20 years.

I still have and use my Stewart Warner Shift light/digital tach/Launch RPM light. I don't know if they still make this model anymore, but it has always worked for me in the footbrake only class. You program the launch RPM and when hooked to brake switch, it will flash or stay on steady (light) if you are over or above the programed RPM. In addition, it is a play back tach for those of us that do not use the electric/air shifter.