Pes Anserine Bursa

My Provider charted that he injected the Pes Anserine Bursa and insists that the px code is 20605 because it is a "medium bursa". I believe that the CPT® guidelines are clear that 20610 is the code for injections to bursas of the knee.

My question is -- do you agree? Would you code it 20610? Also, I've sent him a copy of the CPT® 20610 right out of the book and he still disagrees. Any suggestions on where I can provide information that he will respect?