UC San Diego Freshman Class of 2026 Discussion

I would like to know regarding registration payment for dorm in UCSD. I am going to do SIR and pay $250 for UCSD, which I understand will get forfeited if I get off the UCLA wait-list and accept. Being international student, when do I need to apply for UCSD dorm and pay the dorm registration fee? I would like to delay this payment as much as possible (until wait-list results are clear). Appreciate any help/suggestion in this regard.