When you’re interested in the runtime of several process chains (eg. during last night), transaction codes RSPC, RSPC1 or RSPCM don’t do the trick completely.
Luckily there’s a workaround via transaction code SA38,
report name /SSA/BWT
Execute the program, check radiobutton Process Chain Analysis and press F8.

In the following screen press F5 (=button Process Chains)

After pressing F5, a pop-up will be displayed in which you can enter the desired selection criteria

After pressing F8, the following result will be shown: