An inch sounds like a lot to me. Does it seal at the bottom where it's out a bit more? If it does, that may be as good as it gets or, it may need to be adjusted so that it comes in just a tiny bit more to force the seal.
Adjusting some slides is a give and take deal. An adj. in one place forces an opposite effect somewhere else. Pull the top in and the bottom doesn't seat as tight. Or, adj. so it sits level when out and it's off when in.
It should be even side to side but if it seats well enough that seals fully engage, your probably ok. (can we get a pic?)
Finally, if they can't get it any better you don't want to force them to keep working on it. At some point you start causing other issues especially if you they know exactly what they're doing.
