Migrate email server to another datacenter

We have a cPanel server that is being used only for email. We are planning to migrate it to another datacenter, so the IP address will change. The new server has been configured same as the old, using the same hostname and service SSL certificates, and the TTL of the hostname A record has been lowered to 15 minutes. DNS is handled on a different server - the mail server is not clustered with the name server. MX records are all CNAMEs to the mail server hostname. We are planning to use this process to complete the move: 1. Stop Exim, Imap and POP services on the old server. Block access to webmail in the firewall. 2. Transfer all all accounts using the transfer tool. 3. Update server's DNS A record with new IP 4. Update reverse DNS record for the new IP (cannot be done until forward DNS has been updated) At this point we expect to be up and running again on the new server, once DNS caches time out. We are expecting sending email servers to retry delivery of any email that could not be delivered while the move was going on. Are there any obvious issues with this plan? Other than a service interruption while the accounts are being transferred, we expect this to be transparent to the users. Once DNS has propagated we expect the user's email clients to behave exactly as before the move, with no actions required from the users. Does that sound right? Any inputs will be appreciated.