After you file

Line 20 is the problem … you did not owe $5600 …. You owed $5600 LESS the refund from the original return 

 

suggest sitting tight  until the amendment settles then the irs will either show the credit and refund it or it may take another amendment to fix the problem, but I would not confuse the issue by amending again until the first amendment is processed and you see what the IRS does