As TTB says the restrictions are insurance driven, and there are not that many providers of hull insurance. My policy states mandatory safety pilot until minimum hrs then £75k excess. Even then, a significant claim might make the insurer refuse further cover which sort of destroys the business, hence the continued safety pilot requirement.
Also, I am not as keen on overnight sfh as in the past. The machine is now sufficiently busy that the flight hrs lost from that arrangement would need to be balanced against the flight hrs gained; it is a business, not a club aircraft, after all.
John