can oil filter cause low PSI hot ?

I hate to say it but you can pay me now or pay me later,
I had a guy that bought a rebuilt engine from me that had 20-25 lbs at an idle and after he changed the oil and install a Fram filter the oil pressure dropped to 5-8 lbs so he pulled the engine and sent it back to me wanting to know what happened to the engine.
I put a WIX filter on the engine and put it in my car and the oil pressure was back up to 20 lbs hot at an idle so the guy spent a lot of money for me to to put a good oil filter on the engine. He was told up front not to use cheap oil filters or a Fram oil filter.
So now he knows