Increase Maximum Number of calls per line on TAPI Driver

We are using TAPI Driver (Tapi2 - https: //[login to view URL]) to interact with the Avaya Phone Office 500v2 R11. The issue with this TAPI is that it limits the number of call per extension to 9. See attached picture. Even if the phone can handle 16 calls at the time, the TAPI limits this integration. Can you write a new TAPI similar to the Microsoft one or adapt it to increase this limitation?