It's not a matter of the functions being "kept private". The vast majority of SKILL that runs in IC5141 will also work in IC61 too. If we make a function public in IC5141, it puts the onus on Cadence to ensure that the function continues to be supported in IC61X releases as well. This means that we cannot change those functions, we need to document all those functions, and so on.
So it's a practical trade off, I'm afraid.
That said, I'm happy to provide the code to you as an individual, provided that it is used with care and not used beyond its expected life (i.e. no need to use it in IC614). Please log a service request via support.cadence.com and ask the AE to contact me and I'll provide the code. I just don't want to post it here as it's then effectively documenting the functions for all.