High engine oil consumption

What's the reasoning why my engine is consuming
so much oi I have a 2006 Subaru forester 174,00
miles the engine has been overhauled. I don't see a
bunch of smoke coming out the tailpipe and there's
no known leak on the motor. The mechanic I
bought the car from says that it's normal for
subaru's to burn oil. It has been burning an average
of one court per 100 and 30 miles He claims it the
long trips that's making the oil burn. I do a lot of
long trips with my car usually 80 miles or more. Is
this guy blowing smoke up my a** or can that be
true long trips will evaporate more oil at a average
average rate of 130 miles per quart seem
excessive.  Could there be a leak that the  
Mechanic is not seeing or bad valve springs seals.