Two active plans do not make one answer
Each plan can be active and still require a different estimate depending on which one is primary. The practice needs the coverage order before applying secondary-plan rules.
Subscriber relationship, employment status, dependent rules, and payer records can affect that order. A patient’s assumption is useful context, but it is not always the payer’s recorded coordination.
Verify the secondary calculation method
Secondary plans do not all calculate benefits the same way. Some coordinate up to an allowable expense, some reduce by the primary payment, and some contain non-duplication language that can produce little or no secondary payment.
A verification should state the returned coordination method or mark it unresolved. Applying a generic secondary percentage creates false precision.
Keep the estimate conditional
The secondary claim depends on the primary adjudication. Even with both plans verified, the final secondary amount may not be knowable before the first remittance arrives.
Record the plan order, known coordination rule, and missing inputs so the estimate communicates what is confirmed and what remains conditional.