From the figures quoted it seemed that the extra weight of the fully laden system was just about compensated for by the extra performance.
Reminds me of the time we used to under sling air portable fuel containers (APFCs, commonly known as “bollocks”, because that’s what they resembled) in Belize, to set up a forward refuelling point. By the time we’d got them there, we had to refuel from them to get home...