Why we can't use digital or dial back timing lights with MSD Digital 6 Plus ???

I know the timing light I borrowed didn't read accurately with my Digital 6 box, a specific one is required I believe. I set mine by "feel".

I use a 30 year old Craftsman light with mine, works fine.

i use a craftsman dial back light with mine with no problems.

It has to do with the mutiple spark feature (and it's the case with all MSD boxes).

'Smart' timing lights may not count RPM properly (my Equus does) or trigger the lightbulb on the right spark (should be the first). My light triggers on every spark (which does not make it easy, plus I see the '0' and '180' mark of the damper almost simultaneously - something is wrong here).

'Dumb' timing lights will attempt to trigger on all sparks, but the capacitor that powers the strobe lightbulb can't recharge quick enough, so the light is probably much stronger on the first spark than on the others. Judging from what I've seen in simple timing light circuitry, that's the best hypothesis I can provide.

Now, if all these CDI box manufacturers had the great idea of having a 'tuning' setting so we can have only one spark when we're setting the timing, that would be much better. But they would not be selling simple timing lights either.