I just got stumped!!

Looking at the instore pickup module settings the tax basis is as follows - But where does one select the option I have highlighted in red?? Shipping & Billing are the only radio button slections
Code:
Tax Basis
On what basis is Shipping Tax calculated. Options are
Shipping - Based on customers Shipping Address
Billing Based on customers Billing address
Store - Based on Store address if Billing/Shipping Zone equals Store zone