I'd never heard of these wax rings before so I felt compelled to investigate further. I found
this article which explained it nicely.
A couple of observations...
The guy in the article mentioned using a deluxe ring that incorporates a plastic funnel that prevents water leaking if the wax seal's integrity isn't 100%.
From reading between the lines it looks like you need to bed the porcelain on the wax just enough to sit flat and sealed, but not so much so that the wax is deformed beyond where it seals completely.