Start up iptables script in right way help.

Hi

I have some iptables rules both in administration => firewall and under " sh /jffs/block_list.sh "
Sometimes script under /jffs is to fast and write before iptables in administration => firewall have finished.
That leads to have double ruleset under FORWARD chain.

I have put sleep 20 in /jffs script and it works.
Can this be done any smarter? Wait for firewall to finish and then write my sh /jffs/block_list.sh script?

Thanks!
kthaddock