...do the campany pay you for saving fuel?
Yes. And some will sack you for not doing so.
Somewhere in any FOM you’ll find something like „...economic operation...“ and “...the commander is responsible for the ...economic... conduct of the flight...”.
Until there’s a regulatory limit on exposure (which we'll see probably in another 10 or 20 years), flying eco-levels is the best way to avoid seeing the Director of Operations too frequently.
