According to http://home.rhein-zeitung.de/~ulf.mueller/defa/misc/typen_vw.html which is for the moment the most complete list that I found, the "Typ 2" was only used for T1->T3. So we would have to put Typ 70 and Typ 7D to the T4, and Typ 7H to the T5.
Something that we could also do is to only put "Typ 2" rather than "Typ 2 / Tx", and put the Tx as "mk" number. It will match the system used for the Passat ("Bx"). The only problem with that is that all Typ 2 (T1, T2, T3) will be together, and not sorted by generation.
Another error is the use of Typ 1 for the convertible Beetle, which should be Typ 15.
Same for Golf I (Typ 155 rather than Typ 17) and Golf 3 (Typ 1E rather than Typ 1H).
I could not find any info about the codes used by the three LT generations.
We will also have to find the code of the recent Fox and Eos.

So any comment is welcome about that, I won't do all the changes listed above if the majority of admins do not agree...