No it isnt.
I agree with Dave.
The Case 2 is equal my first example
The Case 3 is equal my second example

Case 4 is a another possibility for the input

Look so in my 3.example here :

3.
Time Force
0 0
20 1
100 0.5
200 0

Then Force 1 and scalfactor 2000
Teh results must be the same Case 2,3,4.

Remark :
Delete the old dyn. Input (.7) before to do change the Time history input

1. Open Input File
2. Then go Windows explorer and delete .7 File
3. Go back to dyn input, and create a new dyn input.