The fact that there is so much misleading and conflicting information out there probably works in your favor.
But it also works against you, as the OP learned. When he/she was checking in, no one knew exactly what to do.
My approach is to assume that a six-month validity policy is
in place and enforced, then get my passport renewed appropriately. I do not travel with less than six months of validity, period.
If I get my passport renewed a year or nine months before expiration, then so be it. That sure beats standing at an airline checkin counter with a ticket I cannot use.