No, this system needs to be rethought. There should be daily or weekly charge. That's how real world insurance works. So why the heck is it so weird in Elite? why as a business model doesn't it make any sense at all?
I agree that the insurance model seems ... well to me odd : as long as you have cash you always have free insurance and only pay the excess when you explode. It should be (IMO) that you pay for insurance up front - you decide on a duration (in game time) and level of cover (tiered ranks, eg: 100K, 500K, 5M, 50M, 200M, etc) and the premium is based upon your choices. You then pay for peace of mind