26 CFR §54.6694-4

1. (a)In general. For rules relating to the extension of period of collection when a tax return preparer who prepared a return or claim for refund for tax under chapter 43 of subtitle D of the Internal Revenue Code pays 15 percent of a penalty for understatement of taxpayer's liability, and procedural matters relating to the investigation, assessment and collection of the penalties under section 6694(a) and (b), the rules under § 1.6694-4 of this chapter will apply.
2. (b)Effective/applicability date. This section is applicable to returns and claims for refund filed, and advice provided, after December 31, 2008.