Currently Project Conversion will not convert a multibeam dataset from a feet to a meters project; the best workflow at the moment is to save as an XYZ then use GeoList Converter. Having the ability to either use Project Conversion to convert, or use Raw File Adjustment in MBMAX64 to convert from a feet to meters project would be of benefit.
Also, adding to the manual in the Project Conversion section that this is not intended to convert from a feet to a meters project, and vice versa