Hi @Jarvis1310, welcome to the forum 
There’s some nuance in the measurement and reporting of these values. For reference, the technical details on the product page are for static bollard thrust, which is a measurement of the maximum thrust that can be generated at a given input command (and corresponding maximum power draw), under ideal conditions for thrust generation.
From your description I suspect you may be measuring the values at some speed, which covers a whole space of values that we don’t currently have data for.
I’d also recommend measuring the supply voltage at the ESC, to ensure there are no significant drops along the way (from an insufficiently strong power supply, or through wire/connections resistance) - there’s some related discussion in this thread.
There’s some kind of correlation there, but the causation is the other way around. There is some baseline of current required for the motor to spin itself at different speeds, and then additional current required to push water (thrust) using the propellers. In environmental/setup conditions where the propeller cannot engage as effectively with the water (e.g. because the water is slipping past by itself) the motor spins more freely, resulting in (generally) less current draw.