An adjuster is applying a policy to a set of facts. Most claim disputes come down to whose description of the facts was written down first and in more detail.
Most small operations know their total for the year and nothing about which work produced it. The difference between those two facts is usually a whole category of job.
The decision is usually made weeks before the conversation happens. What separates a clean parting from a lasting problem is what is prepared beforehand.
A complaint lands in a queue, in front of a person with a script and limited authority. Knowing what that person can and cannot do changes how you write it.