Systems(Virtual Instances with Zero Clock Skew)

Case n)Master Server <--->Slave Server
Case I) RHEL 5.2 <---> RHEL 5.2
Case II)RHEL 6.0 <---> RHEL 6.0

Goal :- TO get Refresh Retry Expire working very fast ( for demonstration purposes of how these attributes works ) and hence assigning them low values as 30 15 60 (Seconds) respectively.

Issue :- These Low timings don't work . For eg. by the end of 30s, our slave server won't go to Master with a SOA RR Query, but indeed would query Master randomly b/w 3-5 minutes subsequently.

Offnote:-
Even in Win2k3 DNS Server, 10S refresh wasn't working as decribed, but using 60s when we had mentioned 10s.

So are there any minimum threshold values for REFRESH RETRY EXPIRE that BIND interprets ?

Note:- Zone Definitions,Zone DB,Firewall,Selinux are PRECISE, and hence there config. hadn't been mentioned.