Thank you so much for your reply! Ill look through the attached link now.
But I had the intention of creating a function that could add all of the results together if the merge fields were present/correct (I work in legal and would want to automate this as opposed to having to manually type it).

I will also continue to look through Paul Edstein's field math document and if I find a solution Ill make sure to post it on here.

This can be automated.

An IF Field contains truetext and falsetext parts. It does not contain subtraction or addition except as part of the test, that would be part of the calculation field.
A calculation field can contain merge fields that are in IF Fields.
Dealing with Fields in Microsoft Word

Hi Charles,
Unfortunately I don't think it is doable then, as this statement is dependent on whether or not the conditional statement can be involved.

For more context, each mergefield is linked to a part of the database we use, such as sourcing whether or not the client has an attorney, and if yes, the charge will be £82, so on and so forth. The charges will then supposedly be added together if they appear as true. Can this work as an if statement? Or do I have to stick with a Formula.

I've not really gotten too far with this