The tech probably told you that to keep it from freezing up (condensation on the condenser fins), but your problem most likely is that the ducts for the front one have probably collapsed or are blocked. Both are not uncommon, as they're not regular metal ducts. Some are only plastic foam and can easily get deformed. Then there's the sloppy manufacturer tech that doesn't clean hole debris out, etc. Pull the grill, look around with a flashlight & maybe a mirror, and you'll probably find the problem.
2010 Montana 3665RE, wet bolts, etc.
2006 Ford F350 Diesel Dually, air bags, Softopper, Aeroshild, etc.