Yes.
True.
I think perhaps you don't know what you are asking.
The problem is that the more ports you add to each table, the harder it is to add additional ports.
For a table of
2 ports, you have 1 measurement.
3 ports, three measurements.
4 ports, six measurements
5 ports, ten measurements
6 ports, fifteen measurements
7 ports, 21 measurements and so on...
The West Med table currently has 14 points, which is 92 measurements.
Part of the point of the junction system is to prevent this exponential growth. So, to add a port to the table is fifteen measurements. Even if each measurement only takes me a minute, it takes a quarter hour on for each port.
That being said, which port are you having trouble with? The spread around the coast isn't precisely even, but its good enough that you can determine how far most things are just by looking at the ports which bracket the one you are interested in. A quick look at the map shows me that the unlisted ports are:
Baltic
Stockholm, Wisby: Just use the Riga figure, except if you are coming from Riga. Then it's about the distance from Riga to Reval, so about 6?
North Sea: Trondheim looks about twice the distance from Edinburgh as London is, so just work out your figure for Edinburgh and add 16. Stockholm looks about, oh, one and a half London-Edinburgs, so call it 12. Stockholm to Trondheim looks like one and a third London-Edinburghs, so, call it 12.
Calais: just add one to the London figure, or knock one off the London figure, depending on your direction of travel.
Rouen, is Paris, minus, oh...five days?
San Malo is a day from the Brittany Junction, I imagine.
Atlantic Coast: Nantes is the only one I can see: I presume its 2 from the Brittany Junction.
There's a scale on the map...get a ruler, divide by 60 miles a day and there you go...
Cadiz is quite close to the Gibraltar Junction, like a tiny portion of a day away.
Almeria is about the distance from Cadiz that Lisbon is, so Junction + of Minus five for most uses.
For Narbonne, just split the difference between Barcelona and Marsellies.