nothing wrong with being a terminal O5. or in the navy, a "termander." my partner looked it I think it came out to $500-600 a month difference in retirement pay. not a ton, but not a trivial amount. depends on what you will be forced to do as an AF O-6.
Moreover, for most doctors, making O6, if it happens at all, it occurs at year 18+, and actual promotion doesn't occur until the end of the NEXT fiscal year. Attaining and accepting that promotion means you need to stay well beyond 20 to fully reap the high-3 benefit of being an O6.
From a purely financial perspective, for almost all physicians but especially higher-paid specialists, every day spent on AD beyond retirement eligibility is a loss. The lifetime difference between O5-with-20 and O6-with-22 retirement is less than the difference between AD and civilian pay for those two extra years.
The choice for lifers boils down to
1) be content with O5, accept the ankle-biter collaterals you must, leave the EP fitreps to others, retire at 20
2) gun for O6, take the huge collaterals you must, scratch and claw to be competitive, beat the odds and get selected for O6 (congrats), wait a year, pin it on, continue with the huge collaterals because hey you're an O6 now for the next 3 years, retire at 22 or 23
or ...
3) gun for O6, take the huge collaterals you must, scratch and claw to be competitive, don't get selected for O6 along with most of the herd
then either ...
3a) keep scratching and clawing for another year chasing a shrinking selection window, hoping to beat the odds, and likely failing to (the numbers don't lie)
3b) accept terminal O5, GOTO (1)
Too much stick, not enough carrot for this termander.