Right, so comparing the same bike with different tyres gives you a basis for comparing the tyres.
I’d want more than just one commute on each to mitigate for the many confounding factors, though: you’ve shaved over 10% off your ride time for an average speed where rolling resistance will only account for something like 20% of energy loss, even without factoring in the additional air resistance of panniers. I mean, it’s not impossible, but it’d be an eyebrow-raisingly huge drop in rolling resistance to cause that increase. When I rode my commute more frequently, I didn’t even find that 3kg of extra bike weight and 7W of drag from a dynamo hub added 10% to my ride time.