Waxless ring and flange extender

[frank19991999]

I am almost done tiling the bathroom floor and the old flange sits underneath the finished floor..
If I use a waxless ring like the one in the picture do I still need to add a 1/4" flange extender ?
Also I read somewhere that waxless rings might not be the best choice for some toilets. Can anyone provide details ?

Thanks,
Frank