Billing For bilateral Facet Injections

Lets say you do a three-level bilateral lumbar facet injection (L3-4, L4-5, and L5-S1). Is the 50 modifier only applied to the first level (64493) or is it applied to the other two levels (64494 and 64495). I was going over my compensation reports and it looks like my organization is only crediting me for the 50 modifier for the 64493 and not for the 64494 and 64495 meaning that I am not getting the wrvu for doing bilateral for the other two joints.
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Tags: Pain Medicine Source Type: forums