The same shifter on my 97 SL320 is very stiff to move from D to 4 so that isn't a good comparison.

My 97 C280 with the same shifter is smooth, I haven't paid attention to any of the clicks.

The extra click might be from the transmission end. Have you adjusted the shift linkage?

For the benefit of others, Park through Drive moves linkage inside the trans. When shifting into 4 by moving the shifter sideways, the linkage is disengaged from the trans and 4 3 2 1 are selected by sending signals to the trans computer.