Ihear ya.For the LiFePO4 package we put in the YEAH BUOY!, their capacity is 90% of rated when discharged at a 1C discharge rate.
Their 100% capacity is stated at 0.2C discharge rate.
Normally people go for the lead package, because shipping lithium batteries over a certain size by air is problematic.
Post office doesn't want any lithiums sent by air. Sellers still mail them ALL the time - I know they didn't travel ground from Cali or such.