I have a Cort A5 Plus SCMS with Bart Mk1 electronics/pups, and an Ibby SR2600 with Nordy Big Singles & Ibby electronics. The Ibby is definitely 'louder' with somewhat similar volume/settings on both instruments & amp, especially active.
I put it down to the Nordy pups on the Ibanez but also their pre-amp; it's pretty loud, seems to add a touch of top end (even flat) which probably makes it seem louder still.
Am I motivated enough to measure the difference/put actual numbers on it ? Nah. I'm just happy to put it down to they're two completely different instruments with different traits which is why I have both of them

It wouldn't really be easy to do an apples to apples comparison between them anyway given the big difference in the pups, particularly.