Calculate Commitment Discount Coverage Rate with Eligibility-Adjusted Denominator

Computes a commitment discount coverage rate using only eligible charges as the denominator. Without eligibility data, practitioners typically divide covered spend by total spend, which produces a coverage rate that includes ineligible charges (e.g., storage services, support fees) in the denominator and may not reflect the actionable coverage opportunity. Targets discount-bearing programs only. Note: Unused commitment rows (CommitmentDiscountStatus = ‘Unused’) have CommitmentDiscountId populated and will artificially inflate both the numerator and the denominator if left in the dataset; practitioners should additionally filter these out for a true utilization-adjusted rate.