Currently it shows the amount of extra fuel requested, even when due to various limitations, extra fuel is (sometimes significantly) lower. This feels like it may be useful for debugging purposes, but not so much for the pilot.
I realize the actual extra fuel quantity/duration is already present in the full briefing, but sometimes when planning a flight one might generate/edit several times in a row to fine tune some parameters, and checking the summary is quicker in that case 
Regards,
Tim
