You might want to post this question at the professional installers forum. Just explain your model number, the spreadsheet name (presumably the correct series) and ask if anyone has any ideas and/or contacts. I think you have as thoroughly researched the problem as anyone I have ever dealt with.

You might want to post the Pronto hex from a few learned commands from the OEM remote and post the Pronto hex, just in case there is some minor protocol variation. Perhaps you have already looked at that.

BTW, I sent you the spreadsheet. Please keep me in the loop as you progress. This is a real brain teaser.