Oil pressure question.

I just picked up my 05 Pete with a C15 Acert engine from the repair shop. They did a platinum overhaul, kit had everything. New head, pistons, liners, heat plate, oil pump, water pump, injectors, rod/main bearings ect.
Block was counterbored.
It had 922,700 miles on it and blew a head gasket (did not get hot).
Had 60 psi oil pressure at hwy speed, 32 at idle.
Now after the OH it has 50psi at hyway and 27 idle.
WHY any thoughts?
Has 650 miles on it since above post.
Still at 50 oil psi hyway, 27 at idle.
Have noticed oil pressure drops 5psi when turbos spool up.

 

Just picked it up on Friday night and was only able to talk to them once. I said something to them before I left about it running a little rough and they did a injector isolation test everything was ok. I'm not building oil, not sure what oil they put in it, was supposed to be Mobil same filter brand (cat). Haven't put a manual gage on it yet. Water temp is 15* higher, oil temp gauge is not working when it came out, another item on my list of shot wrong with their work.