debug level for standard everyday running? and Help with TTL error

[TJ]

What debug level does named need to run at for normal everyday.

and

What needs to be enabled in the named.conf file to determine the zone and 
entry which is the root cause of the errors below?

Jan  3 00:09:32 host.domain.com named[23208]: [ID 866145 daemon.warning] TTL 
differs in rdataset, adjusting 3600 -> 600

Jan  3 02:19:32 host.domain.com named[23208]: [ID 866145 daemon.warning] TTL 
differs in rdataset, adjusting 3600 -> 600

Jan  3 04:24:32 host.domain.com named[23208]: [ID 866145 daemon.warning] TTL 
differs in rdataset, adjusting 3600 -> 600

Jan  3 06:54:33 host.domain.com named[23208]: [ID 866145 daemon.warning] TTL 
differs in rdataset, adjusting 600 -> 3600

Thanks

Ted