I really have no issues with revenue management including POS availability differences, but some of the underlying logic seems flabbergasting at times. About a year ago, when the 747-8 was still on the Singapore route, I tried to upfare my partner's D-class booking on SIN FRA VCE to First and the in-booking inventory showed F0 A0 whereas the SIN POS inventory for a new ticket on the same route showed F7 A5 and the SIN FRA sector was available for a mileage upgrade.