Fellas I have been a Service Engineer for eighteen years and reading service reports from Mechanics is always interesting. I remind myself they are paid to turn wrenches not right novels.
If you are filling the tires for rollover protection only fill them half full to keep the weight below the axle. From your location you may need to add calcium to prevent freezing.
The best way to find out what you have going on is to tee into the line at both ends of the cylinder and check the pressure with a gauge. If it is in spec you may have a hose with a bad liner stopping the flow to the cylinder. If you have low pressure part of the hose that you took off may be...
The reason for more fuel consumtion is the fact you are always lifting the fluid inside the tire. As with iron weights the rim is balanced all the time.