There are plenty of circumstances where a 100% gravel vac wouldn't just be unnecessary, it would be harmful (I'm thinking here of some saltwater tank, and heavily planted tanks).
Now that isn't to say I don't do darn close to a 100% gravel vac most of the time, for many of the same reasons you do. But there are a lot of exceptions, some of them very important to the poster in particular. Gracing people with "something to think about", without providing a couple of the relevant exceptions can lead to some misunderstandings.
As was noted above, the bio-filter in this tank is still establishing itself, and his power filter needs all the help it can get at the moment. An argument can be made that he shouldn't vac his gravel at all until his cycle is well and truly completed.
But again... exceptions... His tank is marginally overstocked with some big waster producers, so in this case, it's a tossup, IMO. Gonna be a long painful process in either case. I think I'd go for a 50% vac for the next couple weeks, but that's just my opinion.