Depends on whether it would be at no cost to you - the landing/takeoff cycle must cost someone, whether it's a charge passed on to the customer or absorbed by the trader in the hopes of scoring a full hold.
For the person/company sending the freight, there would be no cost. The ship (as always) pays berthing/landing fees. Also, a roll for cargo for the players is done as normal. (once/week). The result is what is available and is at one port somewhere (UP, or, one of the Downs) and not sprinkled around. (just like the standard rules, freight isn't split when there is an Up and a Down port)
The vast majority of freight is scheduled and/or already contracted.
Remember, the rolls are simulating small operators fighting for scraps left over/too small to bother with, from the big operators.