tile around toilet flange

Hello,
I had a pvc toilet flange installed on a concrete slab that has a metal or stainless steel ring on top...the part you attach the toilet bolts to. I had to put down a couple new tiles around the flange. My question is, should I grout right up to the top of the flange to keep the flange and the pvc drain pipe below from being able to move if the toilet for some reason shifts over a period of years and causes stress on the pvc pipe as it moves as well, or should I keep the grout away from the top of the flange more to let it keep what little movement there is in the pipe that comes up the concrete floor? Maybe a little movement or play in the pipe is okay for possible foundation shifting. Or am I over-thinking this and it doesn't matter one bit?! Thanks.

Your problem is the flange is supposed to set on top of the finished floor and then be screwed into the sub floor (slab in this case) Since it has been incorrectly installed, what you should do is get an extension ring for the flange that will raise the level to what it should be. Seal the ring to the flange then anchor it all to the concrete. I use lead ferrells and stainless steel screws, but some prefer Tapcon bolts. Either will work. The space between the pipe and the flange should be filled to hold the pipe in place. I'd use Water Plug cement. Any space between the tile and the flange should also be filled so any water getting under the toilet can not pool. The flange definitely needs to be solid. Remember what is under the toilet is functional but not cosmetic.