Mapping Fields Account Name in Leads to Account Name in Potentials

Mapping Fields Account Name in Leads to Account Name in Potentials

I am trying to map a custom field (Account Name) that I created in the leads module to Account Name in the Potentials module. Both are set up as Lookup fields. 

When I use Map Fields to map Account Name in Leads to Account Name in Potentials, Zoho won't allow it. To me this would be a basic requirement so the user does not have to reenter the account information. 

Did I overlook something or am I doing something incorrectly?

Thank you.

John Galich