machan never believe the 'some-say' fuel figures. A 1.5 Liter Auto Transmission car in Sri Lanka would generally manage less than 10 KMPL in heavy traffic and depending on driving style would get anywhere like 12-15 KMPL on the open roads. Maybe you're a little heavy footed or did you re-set the trip for the long outstation trip? Also try a full-tank to full-tank test and calculate. Don't worry too much about it.
I found this site that has info about different cab configurations and bed configurations. I would say this is just for information since here in SL we don't have that many configurations on bed sizes, I guess we only have few options with cab configurations.
https://www.carid.com/articles/pickup-truck-cab-bed-sizes-are-important-to-know-when-selecting-accessories.html
1. What do you call the tall version of a cab which has 4X4? e.g.- LN 106 - DOUBLE CAB
2. What do you call the tall version a cab which has 4X2? - DOUBLE CAB
3, What do you call the short version of cabs which has 4X2 e.g. LN145 - DOUBLE CAB
4. What do you call the short 2 door long body version of cabs? - SINGLE CAB