“Positions” on the site stats page is somewhat misleading. It’s really “data reports made to FlightAware”. The report rate depends on a lot of things that are out of your control - notably what the aircraft is doing (e.g. flying in a straight line at FL390 is not worth reporting frequently). If you’re also using skyaware anywhere (your logs imply you are) then the report rate gets artificially increased while it’s in use to improve the interactive experience there, which unfortunately also shows up on the stats page.
I’d rely more on your locally gathered statistics as they are unaffected by the reporting rate decisions that piaware makes.