Matt4 revenue management are probably at play here. After all it makes sense to maximise revenue on popular, heavily utilised routes such as LHR-DOH. The heavier the utilisation the fewer seats are available for rewards. If reward seats are much sought after then it is sensible to make access to them more difficult (i.e. more expensive) to obtain. 'Supply and demand'!
On the other hand you have commented upon the reverse happening on some routes (higher, upgradeable, ticketing classes for promo tickets). If this is on underutilised routes then this is also good revenue management.
But this is bending the rules regarding PCs use of ticketing class! In the 'knowledge is Power' environment of QR can we really expect revenue management to have any knowledge of PC rules?
Here we are 'complaining' about QR breaking/bending the rules and over on the Sake thread others are complaining that QR will not bend the rules and give them something they are not entitled to.
On the other hand purple1addict could be correct when she says "merely general IT incompetence".
Only time will tell!