You should call Newmar support and see what they say. However, rubber roofs need very little care. Simply wash it with dishwashing, car washing, you choose a couple of times a year. You may also want to add a small amount of household bleach. Some people will use a brush some do not. I'm in the don't not camp. I mix up in a 2 gallon yard sprayer water, soap, bleach and spray it on and leave it for 10 - 15 minutes and spray it off. If there are spots left, I repeat.
You do not need to pay for expensive washing or conditioning products. None needed. However, you may want to spray all the plastic vent covers, AC covers with a uv protectant.