As far as I understood, CUCM uses closest-match logic for call routing.
When a number is dialed, Unified CM uses closest-match logic to select which pattern to match from among all the patterns in its numeric call routing table. In practice, when multiple potentially matching numeric patterns are present, the destination pattern is chosen based on the following criteria:
•It matches the dialed string, and
•Among all the potentially matching patterns, it matches the fewest strings other than the dialed string.
What if the fewest strings are also the same?
For example, two translation patterns in the same partition: 99[5-6] and 99[6-7]
Dialed number is 996, how the CUCM decides?
There are scenarios that are not tested because they're not recommended, you'll never find an overlapping scenario in the SRND as the recommendation or the best practice, because overlapping is NEVER considered a good design.
Why would someone configure that scenario in the first place??