When working with payees during data entry if you just type numbers for the TIN then it is assumed to be an SSN. If you type the dashes then it will be what ever format you typed. Please not you can't just delete a dash you must type the entire TIN.
When importing make sure you TIN's have dashes, or if they don't then you should have a TIN type column with 1 = EIN or a 2 = SSN.