Bravo 3 and gear lube

[lakershaker]

Last weekend my gear lube alarm went off due to a very low reservoir, and I had to fill the tank. I had the sterndrive service done this spring, but it seems that each year I run through a whole tank of gear lube while putting about 40 hours on the engine each year. Is this normal? I want to be sure that there isn't a bigger problem that is being masked.