A common misconception in reporting on the "Dialed Number" field for inbound calls (or equivalently the "DID/DNIS" field), is that the "Dialed Number" represents the actual number a caller dialed from their phone.
It is important to understand the three components of a DNIS mapping in Mitel (ShoreTel):
"Received Digits" is the digits received from the CO. "Dialed Number" is what Dialed Number those received digits represents. And "Destination" is of course where you want the call to be routed.
How many digits you receive from the CO is part of the trunk group configuration. In the example here, the CO sends 4 digits. Sometimes the trunk group might be configured to receive 10 or 11 digits from the CO, in which case the Received Digits really is the number that the caller dialed (barring any translations provided by the CO, such as toll-free numbers). But that is implementation-specific.
What gets logged to the CDR database is not the received digits, but rather the "Dialed Number". And "Dialed Number" is a free-form text field in to which you can enter whatever you want to be logged when those digits are received. Sometimes people use it to represent the actual number that the caller would have dialed, as in the first two examples above. Sometimes people use it to give a logical name to the dialed number, as in the second two example above. Sometimes there may be a toll-free number that is mapped by the provider to a local number, in which case the toll-free number might be entered as the "Dialed Number" so that the corresponding toll-free number can easily be identified.
So what shows up as "Dialed Number" in your reports is completely up to the Mitel (ShoreTel) administrator. It may be a phone number, or it may not be. If it is a phone number, it may represent the actual number a caller called or it may not. There is no constraint on the format of the number. "+1 (707) 766-1745" is as equally valid as "7077661745" or "707-766-1745". Mitel (ShoreTel) will log whatever is in that field verbatim to CDR.
DIDs are a special case of DNIS mapping where the format is constrained by the Mitel (ShoreTel) system. You define a base number that the received digits should complete, and Mitel (ShoreTel) will log the "Dialed Number" in a canonical format based on that number. DNIS mappings however are completely free-form and arbitrary.