PowerProtect DD: REST query "/rest/v1.0/dd-systems/{SYSTEM-ID}/stats/performance" doesn't work

https://developer.dell.com/apis/4208/versions/7.13.0/reference/ddmc_7.13.0.0-1078781.json/paths/~1rest~1v1.0~1dd-systems~1%7BSYSTEM-ID%7D~1stats~1performance/get

The above REST query to get the system-level performance stats doesn't work! I've tested on both DDVE and DD6900, both on DD OS 7.13. Can you please test this and advise how to fix this? I found v3 version of the same query working (/rest/v3/dd-systems/0/stats/performance), but the stats don't tally with the Realtime Charts > File System Operations in the GUI. Is there a proper explanation/documentation for this query?