Difference between revision or appeal and motion to modify protection order

Hello. My ex-wife has entered a protection order against me under false allegations. I need to fight this order because it also includes my 4-year-old son who I am very close with. At the hearing the commission ruled that I shall lose my child. I file for revision and at that hearing the judge said that the Commissioner did not make a mistake in their ruling. Now, I have the choice of filing an appeal or a motion to modify the protection order. The way I understand the law is that in an appeal, no new evidence may be brought. In a motion to modify I understand that this is the same as starting over and having the hearing again from the beginning.

Could anyone please explain to me why one is better than the other. I understand that an appeal cost a lot of money but I need my son back so I do not care.

Thank you very much

PS I am in Washington state