Good point, and a possibility. But the Judge may want to retain jurisdiction through accomplishment of full (one time) payment, as well as due to the "without prejudice" aspect (if something goes haywire at the USPTO). With regard to the latter, in may be purely in the interest of court efficiency, e.g., if the Js made a counterclaim, why have to educate a different court on the matter?, no matter how unlikely the event.
FWIW,
SGE