It probably is 5500mAh. Keep in mind that the higher the capacity, the lower the amperage, generally speaking. So you need to clarify what your looking for. A very high capacity means it will output a smaller amount of power for a longer time going all the way down to around 2.7 volts. I never run my lights to that low of voltage. Once it hits 3.7v or 3.6v you’ve used the majority of the power and I recharge them. So high capacity is not that big a deal to me.
If your looking for high amperage in a FET based light you would want a lower capacity, high discharge battery. A cell like the Samsung 30T 21700 can output huge amps, but it sacrifices capacity to do it. A Samsung 50E sacrifices high amperage to give higher capacity/run time. Then the Samsung 40T is the in-between cell with a nice mix of amperage and capacity.
The battery manufacturers can mix the chemicals to give a cell the characteristics they want.
I tend to not run the high amperage cells because max output is only at high voltage, like 4.2v and the driver needs to be FET based to take advantage of the amperage. Once you use it a while and the voltage drops a little so does the max output level. Plus they tend to heat up really fast.
I use my Sofirn C8F with a high capacity Samsung 50E cell and my Sofirn SP8 I use the Sofirn 5000mAh to limit turbo and give longer run times. Turbo output is not as extreme compared to high amperage cells, but you can hardly see the difference with your eyes. The difference can be measured, though.