well mine is very good, if it as happened to the last few services you must have a leak?
question is if it as happened the last few services ? why dont you check it regular once a week or month it only takes a few min, and as far as the oil light its waist of time cus it only comes on when you are very very low so dont wait for light to come on to say you need oil, running without oil or low oil you can age your engine before it time.
can you see any leaks cus if your using that much you must have a leak, check around filter/drain plug/ sump gasket/ check splash sheild under engine is there any oil on that, check rad and header tank to see if it whiteish in colour, or are you burning it, how was your tempiture reading ?.
Anyway get it checked out as you shouldnt use that much oil
sorry to be so blunt