@aftab371
Sir, are you sure you are doing the correct calculations because I did a rough calculation and your bill for the usage you mentioned is exactly SNGPL has sent you. Plus, the notification for gas price increase is from Jan. 2013, and your bill is for Dec. 2012 where gas price was 6.14% less then what you mentioned. Here is the calculation:
Gas rates w.e.f. 31-12-2012 according to OGRA were:
Upto 100 M3 per month: All off-takes at flat rate of Rs 100/MMBTU
Upto 300 M3 per month: All off-takes at flat rate of Rs 200/MMBTU
Now your gas consumption is 1.010 HM3 i-e 3.259 MMBTU. According to this your Gas charges should have been:
3.259 * 200 = Rs 651.8
However I have been send a bill with Gas charges of Rs 651.8
Also, please tell me why are you applying 2 different price slabs on your bill, when it is clearly mentioned even in your own post that upto 100MMBTU and 200MMBTU. I am pretty sure that if you have interest in cricket then you knows that when a batsman reach 50, this is classified as a half century in his career total but if he goes on to convert this in 100 then the half century is not classified but only a century is classified. His 50 will only counted until he is on 99 but as soon as he makes it 100 his 50 is deleted from his career total and a century is added otherwise he has made 2 "50s" by your logic.
You are wrongly assuming that you have used 100MMBTU gas in the 100MMBTU tariff while the remaining in 200MMBTU which is not how it should be calculated.