Just as family group rates are independent of the number of children in your family, those with children in the high age range will not pay any additional premium over those with younger children.<quoted text>
I have news. When your medical costs, individual or family, exceeds the premiums paid, everyone in the group or with that insurer pays.
You claimed other people were paying the premiums of the kids staying on their parent's policy until 26.
The parents pay those premiums with perhaps those grown adults chipping in.
When costs exceed the premiums paid, the premiums may increase the following year, but then the employer can always change insurers. Unlike the government, there is no retroactive taxation.