I recommend that you study the wonderful web site "www.miklor.com".  Much information available there, answers to many questions.  Given the steps that must be taken to enter the VFO mode, it seems like there is no need to disable VFO, as one cannot just "accidentally" get into the VFO mode.  If you concentrate on programming the repeaters you desire to use, there is likely little or no need to disable VFO.