The game "releases" the rehabs every 13 minutes or so. However just like the money hack, in the fourth prison the values can't be found anymore, I've tried every way, but no luck. Strangely with the money you can find it by searching the profit or loss value (double) -the profit or loss value gets changed back at the original value when buying or upgrading things, but the money gained with the hack gets added to your money. And since it can be changed it suggests that the money value is not server sided.
The rehabs has no other values (that I know of), to hack into. And I get the feeling it is serversided from the fourth prison.