With respect to Propane.
If you have a good digital bathroom scale you will know if they are cheating you or not .. Propane weighs approx 4.2 LB per Gallon.. weigh the tank when empty so you have your baseline or tare wt. and then when filled and you will know exactly how many gallons they put into your "empty" tank.
The larger tanks will actually hold MORE than they are rated for .. I have a couple 7 Gallon or "30 lb" tanks we use for various things like forklifts . Had a guy once UNDERFILL it , and i felt the lack of weight immediately, its quite noticeable once you are used to the Feel of it
, so i asked wtf ? so he says he over filled the other one to 8 gallons and so he dialed the 2nd one back to 6 gals as I had paid for " 2 x 30 gal fills" ,.. turns out it was true .. the scale tells the whole story ..
The Big lot stores in the states and Wal mart have been cheating people for years by UNDER FILLING tanks. like the 20 Lb tanks to 75% of capacity which is outrageous.. they literally put in 3.6 gals , instead of the Full capacity of 4.7 Gals ...
but if you are paying by the GALLON, like in those Larger tanks you have in the DR, you should be getting exactly those Gallons which you paid for ..
So go by the Scale to double check it .
Is it true that some people who are tight on $ actually sometimes pull up and buy just 200 pesos of Propane GAS ?