I think it depend on how much later than the usual shot time. Shooting too much later tonight will mean having to adjust the shot time tomorrow. If you are more than an hour past usual shot time, if you shoot, tomorrow you’d either shoot 15 minutes early from this pm shot time, and every cycle after to get back to usual time, or you can shoot 30 minutes early from this pm shot time once a day until you get back to your usual shot time.
Getting back to 12/12 schedule
For most caregivers, anything more than 2 hours is difficult to adjust, so skipping is fine if you can’t accommodate the schedule changes to get back to usual time, and in your case, no history of ketones.