IIF statement in query - MS-Access

As far as the query design is concern, we may add additional field to do query. Below is the IIF statement on how it is being used..

AfterTax: IIf([sdexr1]="V",[sdaexp]+[sdaexp]0.1,[sdaexp])
say V = 10% Tax ; Then , go for red highlighted Rule 1. If not, go for Rule 2