My buddy came through and got me the IR codes in Pronto format based on the documentation from Sennheiser.

You'd think they'd do better given the kind of gear they sell ($2,500 for the Ambeo soundbar), but not only can Sennheiser fail at writing IR codes (no discrete power - really?), they also fail at maintaining the ones they do have, because their spreadsheet had some errors. Sound mode presets were confused, and the Night Mode was missing. They listed a Night Mode, but it was a sound mode of Neutral. My buddy found the Night Mode toggle code from the learned codes I sent him.

Attached is an RTI .cml file with working codes. Of course, no discrete power, but I haven't gone through all the permutations of unlisted codes that he generated for me.

OK, I can't upload the file here.   I'll figure out where to do that.