......Typically, very few companies buy into that kind of age bracket plan for their employees for that very reason,....
Basically, I disagree with that assessment as:
Anytime an employer shops for health insurance, the potential carrier requires an employee "population analysis", and the ok of the current carrier to release the overall claim experience history of the current group. So, while the individuals in the plan don't pay differing premiums based on age, the company is assessed premium charges based on the employee/family population.
My recent employer recently went to a plan where the employer agrees to pick up the first $1,000 of annual employee/family medical bills, and once the family bills exceeded $1,000, the insurance company kicks in. The employer cut the annual premium per family by $1,300, and based on prior claim experience, the potential savings could be up to 60% of the old annual premium.
Significant!