You can get a semi-automatic way to do something like this. Create manual fields in your schedule for each of your opening types (doors, windows, ect). Then, just add another field that will multiply those fields by a factor of how many extra studs are required per field and add it all together.
extra studs field sample equation: (door count *4) + (window count *5)
To quickly count the number of new windows/doors go to a 3D view, set your phase to New, filter to show new, and mouse over/select everything. Press the filter button, and you will be given a count of how many windows, doors, and everything else you have selected.
Finally, just create a last field that will add the extra stud field to your automatic calculated field of wall length/16".
Select the letter heading of all the columns you don't want to see in the final sheet and hide them.
