Indiana Interstate RV Repair adjusted our slides a couple of years ago. Paul and Kay Cross are EXCELLENT people to deal with, Paul knows DRVs inside and out! They're in LaGrange IN which is about 5 miles from DRV's facility in Howe. Be warned though, he's very popular and he's probably booked out a few months! Phone 260-463-8100
Another option would be Twin Lakes RV Repair also in LaGrange. Jay is ALSO an excellent choice for slide adjustment! He's VERY versed in DRVs and when we first bought our '15 38RSSA and needed some warranty work DRV was "booked" solid and they sent us to Twin Lakes. Phone 260-562-2372 talk to Jay.
We've had both guys do work on our unit and I would NOT hesitate to go to either for GOOD quality work!
Hope this helps you.