Although my roof was still under warranty I applied a coat of Dicor liquid rubber to my roof every year as it was very easy and almost mess free of cleanup using long handle paint roller. Roof always looked nice white and clean. How long will your trailer be out of service for the new roof??? I have heard reports on RV forums that dealer warranty works often takes months before service depending
Since you say bottom shows no sign of leakage or damage or rot maybe a good roof cleaning and application of liquid rubber coating or Flex Seal/Flex Armor may or may not solve the problem and you can have check sent to you. Just one possible option. Good luck to you.
I never had a problem with the roof of my 2003 R-Vision TT by Monaco Coach that was every year exposed to extreme hot Texas and Nevada sun/heat and snow and ice with no cover on outdoor storage lots. You have a newer trailer????