The USPTO has published a further explanation of the patent term adjustment rules in the Federal Register. (69 FR 34283). The purpose of the explanation is to clear up confusion regarding "overlapping" delays under 35 U.S.C. 154(b)(2)(A).
Specifically, the Office has consistently taken [and continues to take] the position that if an application is entitled to an adjustment under the three-year pendency provision of 35 U.S.C. 154(b)(1)(B), the entire period during which the application was pending before the Office (except for periods excluded under 35 U.S.C. 154(b)(1)(B)(i)-(iii)), and not just the period beginning three years after the actual filing date of the application, is the relevant period under 35 U.S.C. 154(b)(1)(B) in determining whether periods of delay ‘‘overlap’’ under 35 U.S.C. 154(b)(2)(A).