Did you give the oil time to drain down from the head? Sometimes fresh oil can be hard to see on the dipstick, I had such a hard time with it on my SDL that I filed the dipstick rough so I could see where it clung! Synthetic oil is much worse about it than conventional.

If you know you added 2 gallons (like newly opened jugs instead of ones that were opened previously), go drive it around until the oil gets dirty enough to make it easier to read.

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]