Lack of this setting may be a reason why calendars are not displayed properly in FSM. Mapping for relevant time zones is necessary because FSM uses another time zone format than SAP.
...
If the found time zone is equal to company time zone (e.g. CET) in transaction https:/
...
/proaxia-prod-doc.atlassian.net/wiki/spaces/PFCC/pages/31953211 and the time zone id in this transaction is maintained (e.g. “Europe/Berlin”), then the time zone id would be taken from the company settings and not from time zone conversion customizing table (/PACG/ECM_TZCNV).
...
If the setting above is not maintained, time zone id can be set in transaction https:/PACG/ECM_TZCNV - Time zone conversion/proaxia-prod-doc.atlassian.net/wiki/spaces/PFCC/pages/72843268. The first field contains a formal time zone while the second one is an up to 50 characters description. E.g. 'Europe/Berlin" can be converted to "CET".
...