You are not getting the engine up to temperature when you are setting the idle. After it has flown then its warmed up good and the idle is a little higher. This is common.....You need to richen your low speed air bleed screw a little or maybe the Regulator just a little. The engine is really close to set properly...

I would say try warming it up good before you set your idle trim to the proper idle rpm. This will ensure that when everything gets warmed up it idles in the same spot as before.

Troy Newman
Team YS