Paul,
No dashes, but we do have a few Invoice Numbers with alphabetic characters in them, not sure why, maybe something to do with credit memos and user error.
Your advice in the Blog to make sure that only Method is used, or only QB is used to enter Invoices etc. when auto ref number assignment is turned on sounds very important as I can envsion easily causing trouble with the Max Number calculation if we enter variously formatted Invoice numbers.
This is a great feature, I hope it doesn't cause a lot of support issues, and I'm looking forward to going 100% Method for some of these business process.
Cheers,
James