Display message with chime says stop engine low oil pressure

This is a rebuilt swap north-star engine, first engine got 187000 miles this one has only about 11000 miles. This stop engine message started about a two years since the swap. I do not put a lot of miles on this car. One shop said oil pressure is fine and replaced the oil pressure switch. But it still gives the message on a sporadic basis, some days it does not do it al all. It seems to be when coming to a stop and when stopped, but can continue when driving, then go off and not come back on. Took it to a dealer who performed a manual oil pressure check, oil pressure is at 12 psi at idle and increases with rpm, should be at 5psi. They replaced the OPS also but the message and chiming was non-stop, they put my part back on and the message stopped but still does it sporadically. The dealer says it must be a faulty IPC (instrument Panel Control) and it would cost $525.55.