Unfortunately that is the "catch22" for removing an excess that is less than the total contribution. Removing only the exact excess amount will create a new excess due to the increased AGI on the remaining contribution in an endless loop. You should always either have the entire contribution returned or have more than the original excess returned so as not to create a new excess due to the increased AGI.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
