I helped my son reseal the lower oil pan on his 1999 C43 (M113.944) last weekend. We used a Motive Power vacuum unit to suck the oil out through the dipstick tube. When we dropped the pan there was still oil in it. We set the pan back in place with three bolts, pulled the drain plug and drained the remaining oil into a graduated container. We measured 14 ounces (350 ML).

We checked the suction tube on the vacuum unit (we had previously marked the suction hose as a visual aid to ensure it would be inserted all the way to the bottom of the pan). The suction tube projected about 3/16" below the end of the dipstick tube extension inside the oil pan.

It appears that the suction method removes less oil.