EveryDNS currently updates the secondary zones every hour on the hour. We are considering adding a button to the website to request a "pull" of your specific zone if demand is high enough. Let support@everybox.com know how you feel about this. We are also considering obeying rfc1996 NOTIFY packets so that updates of the master will automatically cause an immediate pull from axfr.everydns.net.
EveryDNS violates rfc1034 by ignoring your SOA parameters. We unconditionally poll every hour on the hour, no matter what refresh and retry parameters you list. This might possibly be interpretted as a Bad Thing.
To verify that we have permission to AXFR your zone at all, and to verify that we have your up to date zone serial, please visit http://DnsReport.com.