[Canalman]

Your problem is water intrusion and wood selection. I've been selling paint for 7 years now and I see these types of problems all the time. That cracking around the belly hole is the first sign of swelling due to water intrusion. When water gets into any wood whether its the exterior walls of a house that wasn't flashed correctly or your plug, it will find it's way out "popping" the paint off in the process. I remember a few years back Mac had a run of plugs that did that, the bottle darters from the 2004 crazy swap. He instructed me to put a spoonful of epoxy into the belly hole and let it run along the thru-wire, it worked.

On the subject of base/finish consistency this is a mis-nomer. Back in the old days of oil this was the preferred sysytem. Now that VOC regs have taken so much out of the oil paint, it's really only an effective base coat (save a few interior apps. like cabinets etc.), the oil primer will penentrate the wood making a strongly bonded base but subsequent coats will not penetrate one another and that's how oil paints form their bond, through penetration. Acrylic paints are formulated to stick therefore, they are a much better choice for going over oils and oil primer/Acylic Latex Topcoat is now the preffered system for any bare wood surface. BIN is not oil based anyway it's Alcohol based.

Solution: Use better wood... ditch the BIN it's stopping the penetration of the oil, use Val Oil for sealer and if you're going to use rattle cans only let them "tack" before applying subsequent coats this way they will become almost like one coat of paint.