Your last sentence is the truth Drew, many regional carriers and especially practice plan adminstrators interpret this to either their financial advantage (lets pay out less) or due to their fear of audit, even when the coding would be correct. To be more precise,
30.6.5 - Physicians in Group Practice
(Rev. 1, 10-01-03)
Physicians in the same group practice who are in the same specialty must bill and be paid as though
they were a single physician. If more than one evaluation and management (face-to-face) service is
provided on the same day to the same patient by the same physician or more than one physician in
the same specialty in the same group, only one evaluation and management service may be reported
unless the evaluation and management services are for unrelated problems. Instead of billing
separately, the physicians should select a level of service representative of the combined visits
and submit the appropriate code for that level.
Physicians in the same group practice but who are in different specialties may bill and be paid
without regard to their membership in the same group.
So, if structured properly, and your administration allows, you may be able to bill a new when a cornea person sees them first (on a different day). But there is a lot of institution/practice specific culture that you must be aware of and wade through first.