Asset Converter obtains the value from SCCM out of the WMI class SMS_G_System_SYSTEM property "SystemRole". In most cases this is wrong, for instance notebooks are indicated as "Workstation".
The AM Agent obtains this value from the SMBIOS (System Enclosure or Chassis (Type 3)). This can be determined in Windows by the WMI class Win32_SystemEnclosure property "ChassisTypes".
SCCM can determine exactly this value from the WMI class SMS_G_System_SYSTEM_ENCLOSURE property "ChassisTypes", but it's not currently being done.
Client Automation - 14 SP3
Open a Support case requesting fix T5IZ430