Although not common, it is possible and sometimes desirable to run ypbind and ypserv on the same machine. /etc/rc.d/init.d/ypserv is configured so that ypserv is started with S65, but ypbind is started with S13. ypserv must be started first if the two services run on the same machine. On my machine, I start ypserv with S12ypserv. Also, ypbind should be stopped before ypserv is stopped in order for shutdown to be clean.
This is a valid argument but it doesn't really hurt anything. The ypbind daemon will startup and fail but it will keep trying unitl a server is found. Therefore after the ypserv daemon starts then ypbind will complete it's initialization. I will recommend to the developer in charge of ypbind to make this change.