Subtotal to not include tax (from inclusive tax items)

Hey guys, I'm not sure if this should be in the idea area or if this is something that already exists but I thought I would throw it here anyway.

It would be great to have an option to remove tax from subtotals if it is inclusive.
Currently when I do my invoicing I have inclusive tax on some of my items, it removes this tax from the amount section of the invoice which is kind of what I was expecting.
However when you get down to the subtotal down the bottom of the invoices, the tax is reintroduced here then the tax is shown under it and then the total of the invoice in my situation is the same.

I did a bit of a google/search and from what I've read this subtotal is for discounts to be applied but the flow of the invoice gets a little confusing for some of my clients.
I wasn't sure if there was a way to change this other than going though and modifying the tax code to exclusive or something.
So i thought id throw it out here haha.