[1.05.2] Supply convoy number off by one?

[arl]

It seem that suggested number of convoys is off by one

If I set just the suggested number (12) nothing is shipped

Setting to 13 ships everything as expected

edit: attaching savegame.

 

[MartinBG]

The suggested number of convoys is actually the minimum convoy transports required for this convoy to be operable (consider these as convoys used to maintain the route). Any additional convoy transport is going to be used to ship resources in or out from the target province. Note that adding 1 more will enable shipping, but often you'll need more transports to get the desired amount of goods shipped in/out.

That said I'll consider this feature to be working as desired as the player can either leave this to auto or maintain everything manually in which case it is useful to know what is the minimum number of convoys required for the convoy route to be operable (as it is right now).

 

[arl]

Just to better understand, what is the benefit of keeeping a convoy "operable" without transporting anything, so just the minimum number of ships?
If there are no goods moving on that route, the route could well be not existent at all, right? Or is there any "hidden" effect of keeping a convoy operable even without moving goods? Other than exposing that route to enemy attacks, of course ?