Hi Simon,
of course, ProgramData is the right place. I never doubted that. I am just saying, that the context help in Checkmk in not very precise here. We probably forgot to update it, when we split the files between the directories ProgramData and ProgramFiles (x86).
That does not change the fact, that this feature of deploying custom files to sub-directories on Windows hosts, was ever supposed to work as you expect.