Engine Hour Meter

Forgive me for the newbie question but here goes.....

I have a 2010 Seadoo RXP and am using the engine hour meter to track the supercharger rebuilds as I understand it needs to be done every 200 hours. Is there also a time limit? I've put about 30 hours on it over the last 3 summers. I don't ride it hard IMO, 1000 yd bursts of WOT, no jumping and a few sort of tight turns....

Another question I have is does the engine hour meter actually track in hours or is there some other type or format is tracks like miles vs nautical miles?? I watch the meter on my RXP and it is nowhere near an hour when it changes.....it's more like 20-30 minutes of use. Uf it is supposed to track 60 min before changing, what can I go to get it back on track??