The logics I would apply for this tool are
- if the tax code=A1 and country code=AA or is null, then return 1.
- if the tax code=A2 and country code=AA or is null, then return 11.
- Otherwise return 2

Looks like my formula are correct but I am not sure if this is the perfect way to do that. I am asking this due to in real practice I have many combinations and wonder if there is an easy way to get my result.