when i was on stage 3 and greens i was getting around 200-220 miles - this would be less i drove it hard.
Now on stage 4 , 400bhp on motorsport blue injectors and I get roughyl the same mileage per tank and can get it as low as 150 miles per tank if driven hard. But i did get it remapped by ahemd bayjoo and that made sooo much difference.
May be best to get your car resetup - altho this shoudl be done at least once a year.