With the APC 18x12 my 120SP reaches around 5700 rpm. With a Biela 18x12, which has much thicker blades and is much stiffer, I had 5200 rpm. In the air there is no difference in performance.
So I guess your readings are pretty normal (just add a 0 ) but wait with high revolutions til your engine is broken in.

regards
Andi