Not an expert on fuel grades, but did some research on the net and came up with the following link :
http://www.adnoc-dist.ae/eplus/faq.aspx
Go through it and specially read point no.9.
As per my experience the ECO button doesn't really make any difference inf fuel economy. The only difference it seems to be making is the car losing power. So I never use it.
10.5 to 11 is a very high consumption average for a 2.4ltrs engine. Suggest you have the car checked. My worst in heavy traffic driving is 9.0, but my overall average is 8.0. I calculate another way that about Dhs.100 of fuel gives me roughly 650 to 700 kms.
What average is your car giving ? I also drive Optima 2.4ltrs, and the average fuel consumption is 8 litres per 100kms which I belive is pretty decent for a 2.4ltrs engine.
Actually further on, the A/C stopped cooling properly and they later replaced the compressor under warranty. But KIA certainly need to work harder on their A/C systems.
It's a machine, can fail any time. Besides it can happen to any make/model. My friend once got an A/C problem in his 2010 Nissan Altima only 6 months after he bought it.
The A/C of my 2011 Optima works fine overall, but at times suddenly starts emitting a foul/pungent odour. Has anyone experienced anything like this, please share. Also the A/C doesn't seem to cool as well when the car is at stand still compared to when the car is moving.