ppp problems with routing

[pps]

Hello I use freeBSD 4.11 with pppoe.
I used almost default ppp.conf (as in freebsd handbook) for dynamic ip. 
my config is here http://block111.servehttp.com/ppp.conf
Twice a day I restart ppp from cron with `killall -INT ppp` and if the 
new connection default gateway is different then the old default route 
isn't removed, e.g. after ppp restart I have this:
ifconfig ->
     ...
         inet 66.11.172.181 --> 66.11.165.1 netmask 0xffffffff
     inet 66.11.180.20 --> 66.11.190.1 netmask 0xffffffff

before I had
inet 66.11.172.181 --> 66.11.165.1 netmask 0xffffffff
only, but after I sent INT to ppp the new ip has a different dafault 
gateway and the old one isn't removed. Should the old default route/ip 
be removed or not? In my case the old ip becomes invalid.

Thank you