Thanks, Oscar. I was just trying to figure why "nangkadak" seeds were going for so much more than the same seeds from you or Jim West...
The first. Nangka means jackfruit.
As with most things botanical, it's a bit more complicated than that. Unlike other crosses the jack/chempadek crosses don't seem to ever be given a unique cultivar name. Neither is information given about their pedigree. Each cross is going to be quite different also depending on cultivar of the parents, and also which species was used as female (receptor) and which for (male) pollen. I'm afraid that cheena and chempajack are really catch all names referring to a lot of different crosses of undoubtedly varying quality. At least Maryoto is giving a bit of info about the pedigree he's selling. So i really doubt what he has and what we have here as cheena is identical.
Yes the situation is complicated even more when you sprout these crosses from a seed, which will give you even more genetic variation. Really the crosses should be all uniquely named and propagated asexually to maintain any type of quality and uniformity. But i really doubt any of this will happen in near future.