H22A oil pressure

I have a H22A. After I installed the oil pressure meter, I begin to worry my engine.
The meter shows below:
cool engine start - 4 kPa and goes down slowly when engine warm up
normal driving - 2~6 kPa
when idle - 1 kPa

After 3-4 mins hard driving:
idle - 0.5 kPa

I worry the oil pressure is too low and the engine has something wrong. :(

Is there anyone can tell the H22A normal oil pressure is?