Repeat aanswer of your other post:
I encountered this issue as well.
Drove over something, ruining a tire.
Les Schwab tried to run me into 4 new tires to the tune of over $1000, claiming the need to keep the tread depth equal for the AWD system.
Went home and did some reading, apparently there is something to this according to the interwebs.
So I went to Tirerack.com and ordered an exact replacement, and they offer shaving service.
Had the new tire shaved to match the others and locally had the tire mounted on my rim.
Turned a $1000 misfortune into a $200 misfortune. Winning!