Bathroom redo, with ceramic tile.....

Following all the DIY sites & friends' advice, I put down thinset on
my bathroom subfloor, then my backerboard, then I put thinset in the
seams of the backerboard, pressed fiberglass tape down in the seam/
thinset, then put some more thinset over the tape. I thought while
doing it it was pretty level. But now that everything's in place, I
put a test tile down on the seam & it rocks back & forth a bit.

Should I go to the trouble of grinding down the seams to get the seam
perfectly flat? Or will the thinset that goes under the tile handle
this minor hump?