msd80 isn can be changed using autohex without opening dme. please read isn from original dme or from cas if original dme have no comms, the isn will be long isn in this case and no need to bother short isn. write that isn to donor dme from onbench----->msd8xisn---->msd80 option. then do indiv coding for donor dme on car or with cas connected onbench together.