Short ans is NO for all UDP/UCR/ULTS/LTE tests, carrier specific tests and pre-defined test cases. Since all the testing procedures or functions are pre-defined, the required or supported AT commands for automation are thus coded in the test procedures and can't be added. You can only choose the commands from the list in the UE file.
There's one exception is Development Library related test cases. You can insert any AT command at any place in the test procedures since it's defined by the user. In such case, it'll not use the defined in UE file