It shows you how much difference in RPM your throttle is between the two engines. The goal being to keep them in sync and the needle in the middle. Your throttle handles aren't always perfectly aligned and this lets you keep the engines running evenly.
Is it normal that the lake is also moved with a power-off?
When I usually go, I looked at engine rations, even though the engine revolutions of the two engines are almost equal the sync remains moved, is it possible that it is the advance to settle?
All depends on how you use your throttles. Play with them to see how they affect the sync. Not being in sync for short periods like turning, getting up on plane etc isnt a big deal. However once up on plane it is always a good idea to adjust them so they stay in sync. It just keeps from putting more work on one engine vs the other.
Comments
Really, thank you