'Full' glass of beer
It'll come down to the definition of 'costs' taken in context.
If, by the definition of costs, they mean 'taxable costs', that's clear and reasonably closed (although see the discussion on beer below). If they mean any and all 'costs', both taxable and non-taxable that can remotely be associated with the case, that's open-ended and subject to much argument.
A cynic would say that lawyers will naturally argue for that latter, as that gives them more business.
A similar discussion over the meaning of full continues in the UK to determine what a full pint of beer constitutes. It turns out that a 'full' pint is legally allowed to be 95% liquid, with the rest being the head.
The linked article is from 2008, and this one Metro:Here’s how you know if you’re not getting a full pint is from earlier this year.
If I could get away with paying my bills in 'full' while keeping 5% back myself, I would. And spend it on beer.