Not necessarily, others here better qualified than myself but any aircraft performance varies with power settings. I'd guess that a Sunderland cruised around 160mph to and from station but would patrol at lower speeds and so use less fuel. The Catalina cruised around 130mph but would patrol at 110 or even less, with endurance of 20 hours or more thanks to its long glider-like wing. To quote one of the poems remembered by our late lamented Danny:
The Cat was a dandy, the Cat was a Yank
And her crews they called her the f-f-flying plank.