That is about the craziest idea for handling mail I've heard in a while. I'm not sure if I like it or hate it -- it certainly is a bit sad that (presumably) handling of mail is so slow you need to give the client 2 minutes to sort things out.
What happens if you're writing a reply at 16:32? Do you start over the next day?
What happens if you're writing a reply at 16:32? Do you start over the next day?