around here they charge by liquid volume for filling everything, bottles or frame mounted tanks, i haven't pay by the pound in at least 20yrs, even when traveling
frame tanks and bottle have different fittings
maybe there is a regulation regarding who fills what up there in BC ?
yes, even bottles get liquid LP 'pumped' from the 'tank' at the place of fill up
is your tank marked in pounds, or in water volume gallons,
my tank is is 24.0 gallon appox 100#, my last fill up Sunday the 10th
was 21 gallon, i was not dead empty, the fridge was still going up till the moment i turned if off and shut off the tank