Few Questions

with been a new ST owner im unsure with a few things, 1st is how do i know if i have auto wipers as if i put it on the B setting and use the dial it just seems to stay at same speed just different intervals. Second is Fuel, the computer is saying im averaging around 27.8MPG but the needle seems to be flying down is this normal? my route is mainly motorway for 15 mile and 2 mile normal roads, i pretty much filled tank on sunday drove about 32 mile then my normal route for mon, tue, wed twice a day and now i have half a tank does this sound right to you guys? this is with driving carefully

cheers lee