There are two primary ways of using weightings to calculate total score.
Firstly, you can just multiply question score X section X parent section etc.
This is an entirely valid approach which we refer to Arithmetic scoring. However, this does mean that increasing a questions weight will increase it's contribution to the overall total score - effectively increasing the contribution that its section is making to the total. To get around this, weighted scores can be normalised within each section:
Normalised Section score = section weight X ((sum of weighted question scores) / (maximum possible sum of weighted scores))
Normalised scoring usually produces results which users' expect, more so that Arithmetic scoring. With Normalised scoring, a weight applied to a section caps the contribution of that section to the overall score. SupplierSelect supports both approaches.
A longer article describing these two approaches to calculating total weighted scores is available on the SupplierSelect news site.