It is a very correct aproach
The big load comparsion is giving the real imfo about the battery. not the stickers on it!
I have posted before the discharged curves at big loads.
It is 4000 80C made 2011 weight 127 gr/cell full discharged 200 Amps
It is 5000 65C made 2012 weight 133 gr/cell full discharged 275 Amps
You can see the difference betwin the original and the copy
It is 6600 65C made Oct 2012 weight 133 gr/cell.