This legislation aims to strengthen taxpayer due process rights during Internal Revenue Service collection actions by amending the Internal Revenue Code. It provides for the suspension of the period of limitations for filing a claim for credit or refund when a taxpayer is engaged in collection due process proceedings and properly disputes an underlying tax liability, ensuring sufficient time to address the dispute. A key provision also prohibits the crediting of overpayments against a tax liability that is currently being disputed in collection action proceedings. Without the taxpayer's consent, the IRS cannot automatically apply any overpayment to a tax debt under review, thereby protecting taxpayer funds during the dispute resolution process. Furthermore, the bill significantly expands the jurisdiction of the Tax Court in collection due process cases. The Tax Court will now have the authority to review not only the IRS's procedural determination but also the underlying tax liability itself, if properly disputed at the hearing, and can consider equitable tolling of appeal deadlines.