For an '04 you should be using 5w-30 semi-synthetic. Sometimes you have to remind the dealer about this. This year, even my usually sharp guy, thought we all were using 0W-30 full-synthetic.
For the '05 and newer they went to the 0w-30 synthetic. In '05 they also went to a better ring style. But, I think the change was really made to make really cold starting easier. In '05 they also went to a much smaller battery.
If you put in the wrong oil, you will most likely see a change in oil consumption. The heavier oil (10-40) may have reduced oil consumption. The lighter oil (0W-30) may increase it. On my '04, lighter oil (i.e. 0w- 30) did increase my sleds oil consumption noticeably from normal oil (5w-30). But the increase was not significant enough to even begin worrying about.
10w-40 is relatively heavy oil compared to what is recommended. However, our sleds force us to allow some warm up, so you should be O.K. I would not worry about it.