A single test counts toward that exam's 10-Test Library, and a library counts toward the Combo, at the amount you actually paid, while its access is still running.
So a single test to a library is ₩224,000, and a library to the Combo is ₩140,000. The upgraded product gets its own 365 days from the day you upgrade.
The 14 days for a refund count from the upgrade payment. A refund takes back the newest payment first.