You can add trash until the compartment is full and the compactor will not compact the trash any further. The compact cycle time will be shortened as the compartment fills up. During full cycle the ram travels 2/3 of the way down into the trash bucket.
With Humalog's short action time of 3  hours, covering postmeal highs with more insulin can be considered as soon as two hours if a meal dose have been underestimated. Of course, not as much sliding scale insulin would be needed here as before a meal, because some of the meal dose is yet to work.
Humalog is a fast-acting insulin that begins to work very quickly. If you use this medication with meal, use it within 15 minutes before or just after you eat. Never share an injection pen, cartridge, or syringe with another person, even if the needle has been changed.