I have passed the FE exam and I want to prepare for the PE Mechanical HVAC & R exam. I understand that MERM 14th edition has been published for the CBT exam. By the way, I have the 13th version of MERM. I'd like to know if it's okay to study with the MERM 13th edition in preparation for the CBT exam. If anyone knows, please let me know. I would like to study additionally with the NCESS PE HVAC Practice exam.