Mine used a quart every 700 miles when I bought it used.
The origional owner told me it did it from when it was new.
He also told me it burned regular gas.
I used the recommended premium and changed the oil. (Mobil one 15-40)
Now I go 6000 miles , add a quart then change it at 7500.
The use was cuased by the computer adjusted the timing to use regular and caused oil blow by.

__________________
Steve Danville
what i did myself.
CPS
rear shocks
MAS x 3.
SparkPlugs (twice)
Fuel pump & Filter
Window switch
replaced both failed horns with Honda horns.
Cleaned ERG Tube
Oil changes
Oil consumption Fix
Brake Pads
A/C Recharge
Anti-Freeze change X 2.
Front Shocks. Monroe. $90
Mercedes Warrenty Work:
Harmonic balancer,power steering clamp. Cat converters.Drive Shaft Bearing.s
Replaced Outer Lower Tie Rods and front lower ball joints at 156,000 miles