Sorry to hear that it is a few weeks out of warranty.
No they normally do not want to spend over 6 hours replacing a freon coil with a new one. A small leak might be fixed in a short time, but it does not sound like it is a small leak on the freon tubing, as that will normally leak outside. Still that can be a 5 hour repair, and at $100 a hour, - well you guess why someone will replace it with a new unit that has a 5 year compressor failure warranty.
You might call Dometic and see what the warranty length is on your unit.
Good luck,
Fred.