It's funny, because some years ago, I wondered the same thing and even called my shop asking if I bought the wrong head. Here's the deal:
For your snare drum only, you should be using a Hazy Ambassador on the snare (reso) side.
Clear Ambassadors are used on both sides of toms.
The confusing part is that, as you've discovered, the Clear Ambassador box says "batter" on it. But there aren't different Clear Ambassadors for batter and reso. There is only one head and it's used for both sides.
So if you wanted a reso head for a tom, you're all set.
If you wanted a reso head for a snare, you've got the wrong one. Go back and get an Ambassador Hazy.