Sorry for the slow response, been on the road near all August so far, home for 3 days and now I'm off to San Fran in 6 hours. The slow deterioration of the oil pressure, and the need to keep the RPM's higher and higher is exactly what I experienced. I can't say what the actual RPM's I was running as the tach is an aftermarket that is reading way low, thank you PO. Either that or by straight line extrapolation, I can push my bike to 190 mph. Anyway, I ran about 60 miles down the Thruway at about 65~70 mph on a hot day. Went to a meeting for an hour or so, and came back via the secondary highways. It was on the way home that I had my problem. With each stop, I had to keep the RPM's progressively higher to turn the damn idiot light off. Thankfully, it was a simple oil change that did it for me~I was running with whatever came with the bike when I bought it and if I recall correctly the level may have been a bit high - but that was a year ago and I'm on my 5th beer tonight. Now I'm running Shell Rotella-T 15W-40, straight dino oil and Fram filters from Wally-world.
I would suggest a full oil change with filter and then resetting the valves and needles back to stock and then running some plug chops to see how everything is running~rich, lean or right-on. Of course, the rest of your set-up will affect all of this: air filter, stock box, pods, exhaust, etc.
And to pod or not to pod, that is the question. Whether 'tis nobler in the mind to suffer the slings and arrows of outrageous airflow...it's a highly personal question. I'm a fan of the stock air box and foam Uni filter and not big on pods, but others will swear by them, it's up to you. If you do go with them, be prepared to rejet up a bit to compensate for the increased air flow. You'll definetly need to run some plug chops to zero in on the proper settings.
The crankcase breather comment has me thinking some - any smell of gas in the oil? That would thin the viscosity and cause the pressure to drop some. Other things may be a crappy sending unit, or a leaking oil pump. My shifter seal was blown and dripping oil. I fixed that only to find that I have a slight weep coming out of my oil pump. Another project for this winter maybe, it's not that bad but if you have a nasty leak that may be mistaken for a blown shifter seal...it may impact the pressure but I would think that would be a constant issue, not fluctuating.
550K1 Advance Team out.