Yes the horse is dead With 4 pulses per rev the ECU had about from 20 to 80 degrees to calculate the timing, depending on where the reference pulse occurs. That gave the ECU (old or new) plenty of time to do the calcs, but the crankshaft is accelerating during this time so although the calculated timing was correct the crank itself has passed.

With 60 pulses per rev the ECU just counts the pulses from the reference notch until it get to the one closest to the required timing (no calcs, just counting). Then it has only 6 degrees of time to compute the result. You need a faster ECU for that, but today that's ANY ECU.