We have mixed opinions, but both cases are correct in my point of view.
I've applied wax or sealant over the coating, and as perfect observed by Rod, I've also experienced slightly reduced durability when compared to applying to a prepped clean surface for waxing.
I mean, if a wax is supposed to last '10 washes', it'll 'run off the coating' after 6 washes.
What I've noted is that applying something over the coating almost always improve the look (even more, it's the ultimate shine).
To explain the fact I like applying wax / sealant over Back Label coating I'll rely on the same example cited above:
If a wax is supposed to last 10 washes, after 10 washes you'll be back to 'bare paint'.
If topping the coat with a wax (which may (or not) have reduced durability over the coating) supposed to last 6 washes, after 6 washes we are back to 'COATED surface'.
Water proprieties like beading and sheeting will be more towards the product on top, so generally you will notice when your wax washed out from your coating. It's like using a sacrificial barrier to protect your coating.
If we analyze this way, it's pretty easy to see how well the PAINT will be protected always under the coating, with the coating holding an additional layer of protection, so I don't think topping the coat always as excessive or even unnecessary. Depending on case, that maybe what you need.
Nevertheless, you should use the coating by itself for at least until the first wash after application, so you can see how well it behaves by itself. It has incredible properties like shine and slickness that may impress anyone.
It's difficult to expose my exact point of view, I'm looking for words that I can't find right now.
Last suggestion (Coating Booster) looks like excellent addition, as you will be 'topping the coat' with a product with similar properties of coating, 'boosting' it. It's a product I would like very much to try out.
Please, let us know with what you covered your coating.
Any question, please, you're welcome.
Kind Regards.