Manage Buy Order Movement - With Best Itinerary

I have some doubt regarding the function Order Management > Manage Buy Order Movement > With Best Itinerary. How does OTM decide which itinerary is best itenerary?

In OTM help, it states "If an order release has more than one valid itinerary, Oracle Transportation Management chunks the order release using the first valid itinerary it finds and creates the appropriate order movements.
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How does OTM pick the first valid itinerary? Ultimately, I would like to know if there is any way to influence OTM to choose the itinerary which best meet certain criteria in case there are multiple valid itineraries.