Salary dumps

After hearing how the latest releases at WWE were being referred as salary dumps has me wondering do the NXT callups contracts get switched over to WWE contracts or are they are basically the same? I can't see how Aleister Black's contract was deemed so high that he had to be released just to get below the line.

And if these contracts are in fact the same, all NXT and NXT UK talent should be kicking and screaming to stay put where they're at. 

They’re not the same, basically the contract converts to a main roster downside deal as far as I understand.  But now you have guys like Gargano and the Undisputed Era basically staying in NXT forever so I imagine they have special NXT deals that pays them more.