2021年RSU，和ESPP double tax了，今年才弄明白打算填1040x

但是填到line 18 有点困惑，想请教一下

Line 18 Overpayment, if any, as shown on original return or as previously adjusted by by IRS.

Instruction

Line 18—Overpayment

Enter the overpayment from your original return. If your original return was changed by the IRS and the result was an additional overpayment of tax, also include that amount on line 18. Don’t include interest you received on any refund. Any additional refund you are entitled to on Form 1040-X will be sent separately from any refund you haven’t yet received from your original return.

我的original return是 owe IRS 钱，补了税，这里可以填负数吗？比如-6000 或者 （6000）？

我查了好多youtube的例子，original return都是退税，直接line18填退税额，但没看到一列是original return是补税的. 不确定这里line18 如果original return补税了怎么填。Instruction也没提original return 如果owe money怎么填。

还希望有经验的姐妹赐教， 谢谢