When I accept a book request, the system offers me a choice of an "I Can Mail Within Two Days" button (with a 5-day grace period) or an "I Can Mail Later" button giving a choice of five days out (with a 2-day grace period). Since the grace period date on either type of button is seven days later, why isn't there just one button? Are requests handled differently by the system, based on which button is checked? It's not a big deal and I'm not fretting over this; I'm just curious. 

Thanks!

The total with the grace period for both is not 7 days. The [I can mail in 2 days]  has 2 days to mail with 3 days grace period to get it marked mailed (total of 5 days before its cancelled). The [I can mail later] button gives you 3 days longer to mail, but with one day less in the grace period to mark it mailed (up to a total of 7 days before it is cancelled). The mail later option also gives the sender the ability to let the receiver know when they can mail it if they cannot in 2 days.