who the hell is behind the nine tenths of a cent on a gallon of gas

I don't know about you,but when i gas up ,i just fill up my tank...whats the point of letting it go to E....

I do not however, get the whole deal,when you go to get gas ,...who decides/picks/or makes up the  nine tenths of a cent ?...what's the fricking point of this marketing stupidity ......how do you  manage to get the nine tenths ........

So ten gallon would roughly make a cent ...i mean what is one cent of gas ......i really do not know the reason behind this dumb practice ...

I know gas station owners have nothing to do with it, they only get  like a cent or two a gallon,so ....it must  be  these  thieving bastards at Amoco/BP/...etc....i guess it will continue ......there must be something in it for them ....maybe millions of the one tenths add up ......