in my case...as far as i think..you should be careful with the filling stations...in some the machines are tampered...they open up the front case (you can see the place for inserting key, although it is prohibited to open it by law for employees)...when you open it there is a gear typo thingy ...
you move it clockwise...and then you can pour in ur friends cars...meaning..the machine will read actually less than the amount of petrol it is pouring....after that you can always reverse it and then machine will pour less and wil show more amount...
then you can always take it to the point where it is supposed to sit
im saying this...because i have been doing this for my car....long time back in lahore, dha...on the pump partialy behind bowling alley..near hobnobs