Bharat Petroleum [BPCL] — Cylinder weight didn't match

Today I received the cylinder from bharat gas, when I asked the delivery guy to check the weight he said the weight machine is not working after insisting he asked to call the driver which I dialed from my phone and he came with the weighting mechanic, in the cylinder body the cylinder weight mentioned was 15.9 although earlier I received cylinder that was 15.8 and the gas weight was 14.2 so the total weight should be came at 30.1kg but it came hardly 30kg
Now I asked them to weight the empty cylinder, for which they again agreeing but after insisting they did and the empty cylinder weight came around 16.130 grms.
Now my question is how an empty cylinder which weight is mentioned as 15.8 came out 300 gms extra in that case my filled cylinder is not fully filled they must did adjustments in the weight machine itself. Kindly provide me an explanation, I can clearly see I messed almost 300grms of gas if a still consider the +-150 for the weight still 300 is too much.My consumer no. Is[protected], staying in hyderabad pincode 500018. Distributor name is: sama enterprise