What data logger are you using Gregg?
On my LM 2 it talks about "rising edge" and "falling edge" signals.
It says if one doesn't look right try the other.

When I do the timing on my engines with digital 6 (msd) I have to bring the rpm above 3000 so the timing mark will be steady.
MSD said this is because of the multi spark below 3000 rpm.

Hope this helps, Don