Oil smoke under deceleration or after long periods of idling (and at initial startup) is diagnositic for worn valve guides and seals.
Something I have discovered about MBs is that they run much tighter valve guide clearance than american cars and trucks. If the mech that did the work reamed the guides to "typical" standards, they are too loose and leaking, and under high vacuum conditions are pulling oil down the intake valve stems. Will cause you to use about a quart in 1000 miles extra oil. Will usually result in a puff of blue smoke when you start first thing in the morning, too.
Bad seals, or seals that were not correctly installed will do the same thing.
Leaking rings usually cause blue smoke under high load, when the blowby overwhelms the recovery systems and dumps oil in the intake.
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!