Well it depends whether you let the program solve it for you.
If you do as the Help file says and enter Qes, Fs, Mms, and Re to calculate BL using the TAB key to let WinISD calculate BL, then you get these two following screens when you switch between serial and parallel.
SERIAL.png PARALLEL.png
But you can enter new parameters within your project at any time and the software won't object as it will in the initial database entry...
brucek