If it is required to change a start date of a subscription, please be aware rated CDRs dated before the new subscription period will be unrated and end up on the Rating Errors list.
Below the warning when changing a subscription start date when there are rated CDRs.
An other aspect to take notice off is that if the billing of a device is not in synch with the provisioning to the satellite operator, reconciliation of subscription and usage charges will become difficult.