Load balancing with iptables in "nth" mode - iptables

Question

Here is my iptables script, it does not work. Port 9000 is closed, opened ports are 9001-9003. I want to balance loadage between three services located at these ports on localhost. What am I doing wrong?
#!/bin/bash
start()
{
echo -e "\e[32mStarting firewall ...\e[m"
iptables -F
iptables -t nat -A PREROUTING -p tcp --dport 9000 -j DNAT --to-destination 127.0.0.1:9001 -m statistic --mode nth --every 3 --packet 0
iptables -t nat -A PREROUTING -p tcp --dport 9000 -j DNAT --to-destination 127.0.0.1:9002 -m statistic --mode nth --every 2 --packet 0
iptables -t nat -A PREROUTING -p tcp --dport 9000 -j DNAT --to-destination 127.0.0.1:9003 -m statistic --mode nth --every 1 --packet 0
}
stop()
{
echo -e "\e[31mStoping firewall ...\e[m"
iptables -F
}
case "$1" in
'start')
start
;;
'stop')
stop
;;
'restart')
stop
start
;;
*)
echo -e "\e[36mUsage:\e[m {start|stop|restart}"
esac
Thank you.

Answer 1

Here is solution:
#!/bin/bash
start()
{
echo -e "\e[32mStarting firewall ...\e[m"
iptables -t nat -F
iptables -t nat -A OUTPUT -p tcp --dport 9000 -m state --state NEW -m statistic --mode nth --every 3 --packet 0 -j DNAT --to-destination :9001
iptables -t nat -A OUTPUT -p tcp --dport 9000 -m state --state NEW -m statistic --mode nth --every 2 --packet 0 -j DNAT --to-destination :9002
iptables -t nat -A OUTPUT -p tcp --dport 9000 -m state --state NEW -m statistic --mode nth --every 1 --packet 0 -j DNAT --to-destination :9003
}
stop()
{
echo -e "\e[31mStoping firewall ...\e[m"
iptables -t nat -F
}
case "$1" in
'start')
start
;;
'stop')
stop
;;
'restart')
stop
start
;;
*)
echo -e "\e[36mUsage:\e[m {start|stop|restart}"
esac

Answer 2

This will send one package to 9001, the next to 9002 and so on...
iptables -t nat -A PREROUTING -p tcp --dport 9000 -j DNAT --to-destination 127.0.0.1:9001 -m nth --every 3 --packet 0
iptables -t nat -A PREROUTING -p tcp --dport 9000 -j DNAT --to-destination 127.0.0.1:9002 -m nth --every 3 --packet 1
iptables -t nat -A PREROUTING -p tcp --dport 9000 -j DNAT --to-destination 127.0.0.1:9003 -m nth --every 3 --packet 2
You specified the mode parameter twice, -m and --mode.