Has anyone ever done that for a high jump ship?
Probably not.
The sheer quantity of dice rolling and table lookup and map referencing (population of origin and destination, relative tech levels, DMs, etc.) rapidly becomes a prohibitive chore that would slow down gameplay in a tabletop setting with pencils, paper, dice and a calculator (if you do them ALL for a complete readout).
With computer programming and online tools though ...
Speaking of which, it would be great to have an online tool associated with TravellerMap (TravellerTradeMap?) that computes the quantities of cargo lots (not their tonnages, just how many lots of major/minor/incidental cargo) are available outbound from the current location to each of the worlds within (define parsec limit) range using LBB2.81 rules for generating cargo lot quantities (3 major, 5 minor, 1 incidental, for example). From that initial readout of availability, the Players can then narrow down their list of where they want to go next so you don't have to roll dice for ALL of the cargo waiting to leave port, just the destinations that are of interest.
But then it says you can carry cargo for a destination several ports of call later, which is not allowed by the basic procedure in LBB2.
By
basic procedure out of LBB2 ... no.
But LBB2 offers the perfect workaround for exactly this situation (if you're paying attention and know what you're looking at).
Interstellar Charters!

With an interstellar charter, a ship can be charted to transport cargo/passengers long distances beyond the ship's jump/fuel capacity.
Say that someone wanted to buy transport from Regina/Regina to Lunion/Lunion in the Spinward Marches and for whatever reason they want to do so aboard a Jump-1 starship (maybe a Type-Y Yacht or whatever). That's going to be a 22J1 trip!
In order to do that, they would basically need to charter the ENTIRE SHIP for the transport.
Interstellar charters basically buy up the entirety of a ship's revenue capacity at 90% of the standard price
(LBB2.81, p9) for the duration, measured in 2 week blocks (round fractions up).
22 jumps at 10 days per jump (jump space time plus maneuvering to refuel, drive maintenance, replenish life support, etc.) would mean about 220 days.
220 days / 14 = 15.7 ... round up to 16 blocks of 2 weeks worth of time under charter.
So the "local" short haul cargo stuff uses the basic system, but longer range stuff (take this TL=15 drive part from Glisten/Glisten to Iderati/Five Sisters and this is a rush job to get there as fast as you can!) beyond the immediate range limit of the starship falls under the Interstellar Charter rules quite conveniently. Note that interstellar charters may wind up using only a portion of the ship's revenue generation capacity, leaving the rest free for booking along the route.
So if your ship is chartered to carry (say...) 20 tons of TL=15 drive parts from Glisten/Glisten to Iderati/Five Sisters, and there's going to be a Naval Engineer coming along for the ride (to ensure the drive parts don't get "mislaid" or otherwise go missing along the way) ... that's only 20 tons and 1 high passenger stateroom (plus the services of 1 steward) that the ship needs to expend on that charter along whatever path the ship takes to complete the route. Any remaining passenger and cargo capacity left unused
can still be booked by other parties for transport along the way, just like normal.
In other words, the Interstellar Charter pays for a ship to "go somewhere with stuff" but doesn't necessary lock out the ship from being able to generate additional revenue from passengers and cargo along the way. However, if the Interstellar Charter "books the ship solid" with a full load of passengers and cargo for the entire trip, it's up to the captain to decide whether or not being fully booked THAT WAY for the entire journey is worth their time and profit margin.
Needless to say, such charters can easily be used as Adventure Hooks and as ways to encounter Patrons.
The payment covers shipment in the cargo hold from the current location to the starship's next port of call.
Probably the clearest reference, and seems to show you are right, and Mike and myself (among many others) were wrong.
Found a CT citation even more explicit and definitive, allowing for no wiggle room of interpretation.
I give you ...
LBB2.81, p9:
TRADE CUSTOMS
Goods taken on in orbit are delivered when placed in orbit around the destination. Goods taken on on a planetary surface are delivered when off-loaded on the surface of the destination. This custom applies to cargo, passengers, and mail.
I defy anyone to come up with any interpretations other than
port of call to port of call with those trade customs regulations.
It's not per jump.
It's not per parsec.
It's port of call to port of call.
Note that essentially the same language is used on
LBB2.77, p8 (and yes, I checked so you won't have to!).
Now, where's my decoration/promotion/skill up for successfully surviving Rules Lawyer Wars™?
