for mercedes, it depends on the versions
that is
for basic versions,
you can calculate pass once a day and the activation is free all the time
for advanced versions,
you can calculate pass twice and then free activation for 6 months, but after 6 months, you have to pay 50 usd per month for activation
Mercedes odometer correction and gateway authorization:
for bmw, there is no limit
if the activation is expired, the system will help to activate the service automatically
just like vvdi2
BMW FEM/BDC authorization:
http://www.chinacardiags.com/wholesale/bwm-fem-bdc-authorization-for-cgdi-prog-bmw-msv80-49061.html
CAS1 CAS2 CAS3 CAS3+ OBD odometer correction service:
BMW F series coding authorization:
http://www.chinacardiags.com/wholesale/cgdi-prog-bmw-f-series-coding-authorization-55390.html
EGS ISN sync authorization: