Nope, I have the same problem or one similar.
So when I run the same mission with the Hornet, I can change FREQ to either tanker and "talk" to them just fine. Change the player aircraft to F-16 and it will only work with Texaco.
Mission Summary:
Texaco 225MHz
Arco 229 MHz
I can tune to Arco in the Viper and access it via the menu items, had to re-enable them for the test; I normally have my menu disabled. Even when I try to use VA to contact Arco, it "defaults" to Texaco. Even when I say ARCO [pause] APPROACHING FOR REFUEL it pulls up Texaco.
So there is clearly something wrong. Either there is an issue with VA // DCS or a combination of VA // SRS // DCS.
Trackfiles attached.
///EDIT///
I just disabled SRS and tried again, no change. So for some reason VA is not understanding what happens when the pilot changes their frequency. (in the Viper)
This is an example of when I tune the radio to 229MHz and talk to ARCO: (Again, for some reason it is defaulting to Texaco)
AAR_F16_Fail.trk AAR_F18_Success.trk