Are they seeing it as two admin codes bumping up against each other on the same date? Have you checked the provider news and provider resources, or Availity, clear claim connection, etc. for changes? You should always sign up for the provider newsletters and updates from the big plans to keep up with changes. There was probably a change announced for 10/1/25.
I think I have seen where some plans (depending on Commercial, Medicaid/VFC) don't want 90480 if the pt. is under 19 y/o. They want 90460 with a modifier (if counseling was done and documented). Therefore, if you did the two, separate vaccines (with the face to face counseling) on the same date, and that was their policy, you would have to use two 90460 possibly. Either that or they might be looking for a 59 or XS to show it was two separate vaccines for 90480, 90460.