I'll preface this with the statement that, "I'm not an engineer."
They'll likely be along later to give you the thermodynamic analysis.
But, I'll tell you this: I, too, have a Banjo SP-10. My perception is that it puts out a lot of energy.
I also suspects that the "rolling boil" it creates (even with a 10 gallon batch in a 20 gallon SS brew kettle) is incredibly impressive (and, perhaps, a little too vigorous!). I've noticed SRM increases and (maybe more kettle melanoidins) especially with any decoctions done with the SP-10 burner at "full blast." I'm definitely going to turn down the flow on the next few batches (both to conserve fuel, but also to keep from overdoing the boil).
More experienced brewers have suggested elsewhere that you should do decoctions and step mashing at lower temps (lower heat) settings on the burner. You still accomplish the heating, but you prevent the scorching of the grains and keep the rolling boil in the boil kettle to a manageable level.