APIs as listed in https://api.blazemeter.com/performance/ do not give complete results. It looks like they are truncated or not all elements of a result array are listed.
APIs that are used to list items such as tests or private locations carry an implicit limit parameter that defaults to 10. So if you think you list all private locations using https://a.blazemeter.com/api/v4/private-locations?accountId=<accountID> you actually list only the first 10 private locations.
BLAZEMETER GENERAL PLATFORM ISSUE
Specify the limit parameter to list all elements. E.g. in the example above, if you know there are more than 10 private locations but no more than 100, run https://a.blazemeter.com/api/v4/private-locations?accountId=<accountID>&limit=100