When doing an amended return, the meter is reset to zero and may show odd numbers until all of your changes are entered. When you're finished with your changes, the refund meter shows any additional amount owed or refunded to you. This amount is in addition to your original payment or refund shown on your originally filed tax return.
Please see below for further explanation on how the math works when it comes to amended returns.
NOTE: The IRS recommends that you wait until you receive your refund (or pay taxes due) from original return before you amend your return. Then you will need to print and mail the amended return. Amended returns can't be e-filed. More details here
Can I amend if I already received my refund?
How does the refund math work on amendments?
