+2 Flow rate info is nice to have and can be a value in plotting dT vs flow rate to understand flow sensetivity differences, but for stand block testing with a fixed typical condition, fixed pumping power and allowing flow rates to vary as they do in real use is much more desirable. Lower restriction blocks will net higher flow rates as they should. There is a very minor error included in the form of ignored pump heat dump with that but mounting errors far exceed heat dump anyhow so a fixed pump method is the more preferred.
Even if you go to the extreme in testing multiple pump conditons a dT vs flow rate chart still skews the results in favor of the more restrictive blocks. dT vs hydraulic pumping power or a simple low/med/high is a better comparison. Again it comes back to what gear and info most users have on hand. Pumping power using simplified units like Low=single D5 setting 1, Med = 35x 100%, High = 35x2 100% are understood where most users don't have a flow meter so flow rate doesn't speak to them very well.
Anyhow, I would not consider comparing at fixed flow rates if possible. It is useful for creating estimation data, but poor for most block comparison other than just supplimental info.
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