Great discussion. I’d echo the comments on OP’s test. The opening block didn’t really do anything other than wear you out.
I’ve done a lot of Ronnestads for breakthrough testing because you don’t have to worry about testing and they are more “frog in a pot” where you think they’re easy to start right up until you’re just about vomiting at the end. I’d also agree that sometimes the generated sigs seem really high, but to be fair, when I’ve then tried 10 to 12 minute efforts at the suggested power, I could do it, just.
Last point, remember that your “FTP”, or what you’re used to seeing from other systems is equal to your Xert 60 minute power, which is most likely lower than your Xert TP.