My responses to all ... so far.
Poli Glow is $50 per quart.
I called Poli Glow before doing this, and they told me it would work just fine, on top of ZEP, which they said is the same chemical makeup, except for the UV inhibitors.
I also talked to ZEP cust service. The lady said that they have LOTS of calls from people using it on motorhomes. Most all of them were happy. The only CAUTION is that normal WAX is petroleum based .. ZEP / Poli Glow is water based ... therefore... it is wise to put a harse wax stripper on the coach before applying the ZEP, and as a result, it will adhere much better !
I will give an update in 7 years ( unless I sell it first ) .. and let everyone know. STAY TUNED !