This is done purposefully by design, and is correct. ALL high-end data integrity systems work this same way. It is done like this to maintain the accuracy of the business practices in place at the time something was created. If you were to alter a policy, long term reminders, price, description or even changed the consumables on a service, you would not want that to apply retroactively for all past jobs dating back to the dawn of time! That makes everything invalid. All those changes should, and DO, only apply from that point forward. This is the correct way to do things.