Brian, the reason you notice the higher rpms at the end of the flight is the total dynamic head still has an effect on these engines even though they have a regulated fuel system...With the new composite flapers its not as noticeble...Its normal to see this when you are running on the edge...Not a bad thing...Your not going to hurt the engine, its just that the richer settings hide this condistion, because of the cooling effect of the fuel....
What I do here is just try to richen without loosing any power, and notice the plug...These are Very Very small adjustments..Like 1/32...
Remember you lean the engine, so you must first redo your throttle curve just a tad .....
Do not go any leaner on the needles...
You need to just fly the thing now, and not worry so much about the power...I would still take it easy til you get atleast 5 gals thru it..
Regards,
Bill