Lead Source Data in the WebSite do not match the API return

Hello Keep Support Team,
I am requesting the Lead Source Data through the API in the following order:
First I am query Contacts table for LeadSourceId by the ClientId
Next I query LeadSource table for LeadSourceCategoryId using the LeadSourceId from previous step
At last I query LeadSourceCategory for the Name field using LeadSourceCategoryId from previous step

I have several clients that display a different Lead Source Data (from Marketing tab) than I am getting through this process.

Is my process not correct?
What can I do to get the correct Lead Source Data based on the ClientId?

Thank you in advance.