In everything that cielab promotes we always suggest to customers to move to Pantone standards with properly generated media and profiles, this is an excellent workflow that works really well when your system is properly configured.
Roland Versaworks however does not support Pantone in the way that most other Rip’s do with either included, or user loaded look up tables “LUT”. That said, we still find very good accuracy results when using Pantone within Versaworks but ONLY when a very high quality colour profile is used.
If you need accuracy, make sure that you have custom profiles generated onsite. If you already have this remember that not all profiles are equal and the accuracy also has a lot to do with experience and quality of equipment used to generate the profiles. If you have all of this organized and are confident that the media settings that you are using perhaps you should look into a Rip software that does support Pantone properly such as Flexisign or Photoprint.