After you file

Did you pay the original $500 you owed?  No you only get the amended refund.

 

The amended return is only for the difference you get back or owe.  I think the cover sheet shows what the original return WOULD have been if you did it right the first time.

 

Go by the actual 1040X.  Line 18 should be your original refund amount and line 22 should be your additional refund.  If you paid on your original return it will be on line 16.  If there is an amount owed with the amendment, it will be on line 20.