Run time to a 24 volt cutoff because the effects on the capacity are clearer.
On the closeup graph view C1, C2 and C3 are the capacities for 2 amps, 1 amp, and .5 amp and lower. That means at this cutoff voltage the ultimate capacity is reached at .5 amp and anything less for current drain does not lead to a higher A-H capacity.
C1(2) is ~ 7.0 A-H
C2(1) is ~ 7.35 A-H 5.0% increase with respect to 2 amp capacity
C3(.5) is ~ 7.6 A-H 8.6% increase with respect to 2 amp capacity
So runtime for 2 amps drain is 7/2 = 3.5 hours.
The other runtimes for 1 amp and .5 amp are 7.35 and 15.2 hours.
I've left off some of the units in the equation for 2 amps but as a check A-H divided by amps gives a result in hours so the units are dimensionally valid.