Your son should have obtained permission for the move before making it. Even so, extradiction is unlikely for a misdemeanor charge, but a warrant will likely issue. That means your son could get arrested repeatedly if they choose to not extradite. Each time he will have to post bond or wait until the arresting law enforcement agency receives word that he will not be extradicted.
That said, it seems that the probation officer may be most interested in getting the fees paid. Perhapes that person will change his/her mind if the fees are actually paid, if all other conditions of probation have been met.
If not, it's possible to petition the Court for a change in supervision, but when there are issues with the current supervisor, the courts tend to be less accomodating. However, a local attorney may be able to overcome any objections or difficulties on behalf of a defendant.
Get the fees paid first, and then see what kind of response you get about the rest.
This is a general description of legal practices, and is not intended to be relied upon as legal counsel. There is no attorney-client relationship established by the answering of this question, and no expectation of representation in offering this general information.