A true up is the moment Adobe asks you to reconcile what you have deployed against what you have licensed and pay the difference. A settlement is the same exercise after a formal audit or compliance review, where Adobe asserts a shortfall and attaches a number to it.
In both cases the figure that lands first is an opening demand, not a verified debt. It rests on Adobe's measurement of your estate, Adobe's interpretation of the usage definitions in your contract, and Adobe's preferred remedy, which is usually to buy your way back into compliance at list price.
Every one of those three foundations can be tested. The count can be wrong, the definitions can be read your way, and the remedy can be structured for far less than the opening number if you negotiate it instead of paying it.
