Moment of truth in advertising zen: Mexico

Boing Boing reader edmz says, "Gas (petrol) stations in Mexico are not famous for delivering what they must. So I was pleasently surprised when I saw this ad in one station, probably to gain customers, that reads 'Litro de A Litro,' which basically means a 'A Full Liter, Nothing Less.' On a side note, all mexican gas stations are privately owned franchises of Pemex, the government company that handles all matters oil.
Link.