I have seen some fares that are not typical. NYC-MNL was just $1676ish ai for next Feb '11 in B fares.
The Y fare was something like $4500+ and even Ms were higher than some of the B fares. I have to go to MNL in Feb, and so was watching the fares. This fare is usually at least $2600 for M, so I got it and used some PMUs to UG.
It seems to be necessary to check the fares for upcoming big trips regularly lately.