I sell some electronics that if bought in large quantities get a discount on the whole total.
Here is an example:

1-4 $279 a piece
5-9 $219 a piece
10-35 $199 a piece

So 4 would cost a total of (4*$219) $876 and not (4*$279) $1,116

Right now I don't see a way to accomplish this with Commerce but if there is a way let me know.

Maybe this might be the one? http://prntscr.com/6d4xln

Its not though that one if you read states it will only discount 1 that is in the basket.