Which takes precedence for piped text, pre-existing embedded data or the value in the query string?

I am running a CSAT survey where customers rate their account managers. I am storing the account manager's names in embedded data. Some customers have multiple account managers, but only one account manager's name is stored in the embedded data field.
To get around this, I created direct links for each account manager-customer pair. Then I appended the name of each account manager to the end of each direct link using a query string. In at least one case, the wrong account manager's name is appearing in the piped text.
Does having a previously defined value for embedded data override the value specified in the query string?