RT_SB_INS_Vpt4_Offset: INS Virtual Point 4 Offset
RT_INS_Vpt4_Offset: 143, 48 (0x8F3020 + unit id) (0x3F0)
Bytes 0-1: Virtual point 4 offset X (+ve ahead)
Bytes 2-3: Virtual point 4 offset Y (+ve right)
Bytes 4-5: Virtual point 4 offset Z (+ve below)
Resolution of offsets is m / 1000.