Yes you can use hypothetical data to skew data and the shorter the barrel that you use the more of a disadvantage that it is to the larger capacity cartridge.I personally have not seen any commercially available 7mmremmags with 22" barrels and even if they are available ,they would certainly be a very small minority of the 7mmremmags available.
Lets be realistic here and use the barrel lengths that the rifles chambered in these cartridges are actually sold with.Since Browning and Winchester are the originators of the wsm's and the majority of the rifles in use that are chambered for the wsm's are Winchester or Browning rifles, lets use their data.
The model 70 rifles sold in 270wsm are equipped with 24" barrels and the model 70's sold in 7mmrem mag are equipped with 26" barrels.The a-bolts sold in 270wsm are equipped with 23" barrels while the a-bolts sold in 7mmremmag are equipped with 26" barrels.After all most people are buying rifles chambered for the the wsm's because of their shorter overal lengths and lighter weights. .
Therefore the 7mmremmags not only have a larger case capacity,but they are also usually equipped with longer barrels.The combination of the larger case capacity and longer barrel that allows the 7mmremmag to better utilize the larger case capacity, does result in the 7mmremmag producing more velocity with bullets of equal weight.
The rifles that I chronographed that were chambered for these cartridges were real rifles using real barrel lengths which might explain why my experiences differ from yours.