Because of the tap tempo issue, I had to roll back to 2.82 from the 2.9. I can confirm that on 2.82, the tempo light and the timing of the unit are sync'd. What I can also say is that if I play a lick on the up beat the delay will happen when the light is off, thus giving the impression that they are not together, but they are. The light is flashing the time from when it was put in. The sound of the effect is timed from when the note is struck. It is very possible that all of you disagreeing about the light are all correct. On 2.82, if you play in time with the light, the sound will be in time with the light. If you do not play in time with the light, the sound will not be in time with the light, but it will be in the correct time. Hope that helps.