Go ahead and remove the molt, nothing to be gained from leaving it in. Time between molts will vary depending on species and health of the shrimp in question. Adding supplemental iodine to the tank can actually cause excessive molting and result in the death of the shrimp. This is one of the reasons why testing iodine levels is so important if you're going to supplement iodine.
"Listen to some of these guys talk, and it's like they were born from their momma's belly with a fishkeeping encyclopedia in one hand and an API kit in the other" (unrevealed).