My IO-520 dipstick was "wrong" too until I found that the tube it slips in was not seated all the way into its socket. That tube can hang easily up on the edge of the socket it goes into. Make SURE it's all the way in and report back.
For Pete's sake. Read my post again. If a bug gets into the oil inlet port of the engine, the center point of the oil filter, it gets pushed into the galleries and can end up in crankshaft galleries that are easily occluded by small things like bugs. There are tiny oil passages in con rods, too, to squirt oil under the piston head and to lube the wrist pin bearing in some engines. Lifter bodies have tiny oil inlet holes, and through them the rockers and valves are lubed. Any of these can be blocked. The relief valve, in an aircraft engine, is not always in the pump. It is often at the end of the entire oil system and dumps the remaining oil to control pressure. Even there, debris can get lodged under the valve and ends up lowering oil pressure at lower RPM. Besides all that, the relief valve in the engine OR the filter has nothing to do with bugs or other stuff getting into the system and clogging small passages. Nothing.
No use buddy. He can't read and proves that with each post. Plus me and you are mere mx hacks in his world who got our certificates out of a box of Frosted Flakes. Personally, I think he's stuck in a basement somewhere in the PNW playing Flight Simulator 98. But at least it makes the day go by faster....
That's the oil draining out of the galleries that feed the bearings, lifters and so on. With the filter in place and full of oil, the oil pump upstream of the filter prevents much of that.
I once saw a lint free towel get into an F/A-18 engine, twist itself into a mini rope and cause a ton of damage to the engine. The maintainers were floored as the paper towel could easily be torn by itself, but once it twisted itself into a rope it was stronger than anything they expected.