DB_FILE_NAME_CONVERT/LOG_FILE_NAME_CONVERT values in Note 2283978.1

Doc ID 2283978.1 gives an example of using RMAN restore from service in 12c. On point #9, it gives an example of DB_FILE_NAME_CONVERT='+DATAC1/boston','DATAC1/chicago' for the standby, whereby Primary is Chicago and Standby is Boston (similarly for LOG_FILE_NAME_CONVERT). My understanding and usage has been that LOG/DB_FILE_NAME_CONVERT is applicable when a database is/becomes a standby and its pairs of strings are the first string is the pattern found in the data file names on the primary database, the second being the pattern found in the data file names on the physical standby database, and so forth. The example seems to reverse this which I