The PRG route isn't being increased, it is listed as being reduced from 2 to 1 daily? The reductions elsewhere may be what is allowing any increases to be made if the overall system wide capacity isn't actually changing much?
Anyway, I don't think it needs over analysed at this stage. The adjustments have been made, it'll be back to daily from April (runway works aside), and the CAA stats will reveal the route's popularity in time. It's still an increase in the overall DXB-Scotland capacity which I think is how EK will be viewing it given the proximity of the airports.