IMO, that 1.5C "rating" has no significance. Lipos should not be charged at greater than 1C (unless otherwise specified). 1.5C is also not a way to measure current, unless there is a capacity thrown into the mix. But since there isn't, we can't make any assumptions as to the actualy charge rate (in amps).

well it does say, "up to 9999mah"

But that doesn't mean that it can do 1.5C at 9999mah. I think they say 9999mah because the LCD display can only do up to 4 digits, so batteries with capacity into the 10Ah range won't display properly when fully charged. I'll email MRC and ask what the actual charge rate is at different cell counts.