Billing professional component on twin gestation nst's

More and more of our patients are pregnant with twins. For obvious reason these patients are followed more closely. Our doctors are reviewing two fetal tracing, I would likewise desire to bill for the additional work they are doing. I have tried 59025 -26 with two units, these are currently being denied. I have tried bill both
59025-26 with the second code having additional modifier 59. This has also been bundled and denied. Is it inappriopriate to bill the second tracing? I feel the additional work should be compensated.
any suggestions? Thanks:)

Fetal tracing for twins

What about the 22 modifier w/ records to show prolonged service.