Why do insurance firms cut reimbursements despite having leftover insurance cover?

Health insurance companies often cut reimbursements on claims despite the insurance holder having leftover coverage. This is because the companies place room rent limits and treatment sub-limits on claims, which can affect how they calculate the final reimbursement amount. A room availed at 50% more expense than the policy's limit may proportionately cut the reimbursement claim by 50% overall.