Workaround to mixing aggregate and non-aggregate formulae

Workaround to mixing aggregate and non-aggregate formulae

I made an aggregate formula that works but then realised I need to take out VAT from personal contracts.
The code for the formula that works is as follows:- sum_if("Vehicle Orders"."Status" = 'Delivery Arranged & Confirmed With Customer' OR "Vehicle Orders"."Status" = 'Finance Documents Accepted' OR "Vehicle Orders"."Status" = 'Finance Documents Pending' OR "Vehicle Orders"."Status" = 'Finance Documents Received' OR "Vehicle Orders"."Status" = 'Invoiced' OR "Vehicle Orders"."Status" = 'MIGRATED ORDER' OR "Vehicle Orders"."Status" = 'New Order' OR "Vehicle Orders"."Status" = 'Vehicle Delivered' OR "Vehicle Orders"."Status" = 'Vehicle In Production' OR "Vehicle Orders"."Status" = 'Vehicle In Transit To Dealership' OR "Vehicle Orders"."Status" = 'Vehicle Live' OR "Vehicle Orders"."Status" = 'Vehicle Order Confirmed With Dealer' OR "Vehicle Orders"."Status" = 'Vehicle Order Sent to Dealer' OR "Vehicle Orders"."Status" = 'Vehicle Ordered',"Vehicle Orders"."Sales Commission",0)

I then tried to put it in an IF statement that says when the contract type is personal, divide the commission by 1.2 to take the VAT off, but it says "Mixing of aggregate functions and non-aggregate columns is not allowed".

I've been trying to think of workarounds but I'm a little inexperienced coding. Any help would be appreciated.

Thanks,

James