I've never heard of this happening. The base amount of restitution ordered typically cannot be waived. Any interest that collects can be waived. Perhaps that is what the person you spoke to was referring to.
The information provided in this answer does not create an attorney-client relationship and is not considered to be legal advice.
I am not a WA lawyer and cannot comment on matters of WA law or procedure.
But, I can tell you that were this case in Florida, where I have been a practicing criminal defense attorney for 22+ years, then the answer would be a resounding "NO". Restitution is established after either an agreement or an evidentiary hearing and, once ordered, is not subject to discharge. If it is a condition of probation and is WILLFULLY not paid then probation can be revoked and the probationer can be incarcerated. If it is simply a "criminal order of restitution" with no "strings" attached then it remains in effect until it is paid, in full. If a payment plan is established and breached, while the former-Defendant cannot be jailed for non-payment, s/he can be tossed into collections (suffering collateral consequences of being in collections) as well as having her/his driver license suspended. The criminal order is not dischargeable in bankruptcy and stays with the debtor forever (like bad luggage).
All that said, again, that's FL law and procedure, I am not a WA lawyer and you are best advised to find a Seattle, WA area criminal defense lawyer, engage in a meaningful consultation and get yourself some advise which is legally sound and has been custom tailored to meet your needs in your case.
I hope that I have been helpful in answering your question.
First, second and third: No attorney-client relationship exists by virtue of any Q&A with Michael A. Haber, Esq. on Avvo. Fourth: Anything that you post on Avvo (or on similar sites) or on any social media is by its nature public. It is essentially an admission / confession and can be introduced into evidence as a statement against your interest in a subsequent legal proceeding. Once posted you lose any reasonable expectation of privacy, so, as this is an open forum (with no privilege attached), please be extra careful when considering what to post online (forewarned is forearmed.)
I agree with my colleague. It may be possible to get the interest way, if he made a good-faith effort to pay the actual restitution. However, the base amount is owed to the victim of the crime, not the court. The court is unlikely to consider waiving this. Twelve payments of $50, or a total of $600, is not likely to convince the court waive anything. Usually, the court wants to see most or all of the principal paid before considering waiving any interest. I'm assuming this is a collection agency that told him this?