Most "idiot light" switches turn on at 7 PSI, so anything above that is probably OK. As long as the bearing furthest away from the oil pump gets an adequate flow of lube, the pressure is irrelevant. I'm not terribly upset with anything above 15 PSI at a hot idle. Cold engines will normally run 30-40 PSI at idle, sometimes more. The reason oil pressure builds up at all indicates the pump is delivering more oil than the bearings can leak away. If the bearings, lifters, etc. are consuming exactly what the pump delivers, no more or less, the pressure would be zero, yet everything would get lubed. Oil pressure of any amount is an assurance that there's more oil flowing than necessary, as long as that pressure finds its way to the far end of the oil system.
Jerry
