It is NOT a combo code. It does accept advanced codes.

Even if I hadn't known that fact, the symptoms you describe are not the symptoms you get from a setup code that can't use advanced codes. I think your symptoms mean that you have filled the section of the 9960's memory that is used for KeyMoves and Macros. So you need to delete some KeyMoves or Macros before you can add any more.

For rarely used advanced codes, you may decide to skip making the KeyMove to bind the advanced code to a key, and just use the advanced code directly when you need it.

To use it directly:
1) Do a short press and release of Setup
2) Key in the first 2 digits of the code
3) Aim the remote
4) Press the third digit. Hold the third digit as long as you want the signal sent.

The better solution is to use JP1 so you can have better use of the 9960's limited memory.