Our charterer required we use weather routing for ocean transits during the winter months, it was optional otherwise. The way it worked is the routers would first ask me what route I planned and I’d send them my planned route. Mostly they’d agree with my proposed route. Sometimes they’d recommend some modifications along with the rational behind the recommendations.
If I didn’t agree or understand I’d send them an email.
I never had any significant weather issues on an ocean transit nor any out of the ordinary delays.