Honestly, I'm with Chénier on this. I see absolutely no reason for the sea zones to be set up deliberately to make the old sea routes take longer.
Sea zones are clearly not placed based on any particular geographical boundary. They are placed so as to split up the ocean reasonably evenly. There's absolutely no reason why the sea zone should make it take an extra trip way the heck out north to get from Port Raviel to Paisly.
Your argument, Tom, makes sense for land-based regions, and might make sense if there was some feel to the sea zones that there was some kind of actual geographic (hydrographic?) or meteorological reason for most of them to be split up the way they are. But with all the straight edges, they're clearly just, "Well, we'll call this part the Sea of Silence, and that part the Sapphire Deep. Where's the split between them? Oh, I dunno, how about....there."
