MP4.2+6.0

You may be lucky. But, realize the belly pan(s) are under there. If the shop simply wiped them clean, let alone degreased, it takes a while for the oil to build up enough to start running off the side or back of the pan somewhere.

FWIW, among the single biggest short and long term mechanical diagnostic tools I use informally is the belly pan. Always some hassle to pull and replace--even if it is in pretty good shape w/out a lot of road damage. But, since it can be under there for as long as a year and 10,000 miles, I can zoom right in on even small leaks of oil, coolant and a variety of fluids. They usually have a characteristic color, feel, residue or other things, plus usually you can see the general area the offending drip is centered on. Sometimes it drips onto an exhaust and burns off, but then that usually gives off a characteristic smell and marks or residue if you know the physical signs.

Meantime, cross your fingers the "plumbing" isn't just "backing up" on top of your belly pan for now.

TFT

It's been 7 weeks since it was in for service and still not a drop of oil under the car.
I guess maybe I got lucky.

Panelhead

Are you planning on swapping back on the next oil change?

TFT

No. I don't want to tempt fate.

EricVonHa

If this has not been repaired yet, it is worth a 2nd opinion from an Audi specialty shop.

Besides the obvious oil filter seals and gaskets at the top rear of the motor, there is something else worth examining at the rear of the motor.

There is an oil separator that resides near the oil filter base. This can be commonly cracked if the car has had any
service requiring the front clip of the car to be removed (motor can tilt, causing cracked components).

The trick is to clean the under car surfaces carefully and put some hard miles on the car and re-examine the situation.