What they're calling it is correct, remember having a book can be helpful. So feel free to get that replacement part but remember, cleaning the actual egr valve didn't guarantee that that sensor on top of it is working correctly. I guess the only way to find that out would be to replace one, the other, or both one at a time. Confide yourself in knowing you'll still be money ahead because you're not paying someone else to do this, so if you have to ultimately replace them both to resolve the issue you'll be "even up" at worst. The truth of the matter is most shops, but not necessarily the ford dealer, are guessing at something like this anyway, but not revealing that to you ever. But will still charge you fully to be the "guessers" or "replace men" as opposed to the "repair men" we hope they really are. The ford dealer of course, who has actual experience with this exact problem, has of course abandoned you, us, and the Aspire.
If you don't believe what I've told you, stick around and look/search the horror stories about different members trying to get front wheel bearings done correctly. Real disasters there, with real additional, unforseen costs to go with them. That my friend, is as straight an answer as you're ever going to get.
Good luck, and feel free to do a write up on the ultimate solution.