45 CFR § 2105.16
When can the Agency suspend the basic time limit?
April 14, 2021
(a) The basic time limit in §2105.15 may be temporarily suspended for the time it takes you to respond to one written communication from the Agency reasonably asking for clarifying information.
(b) The basic time limit in §2105.15 may also repeatedly be temporarily suspended for the time it takes you to respond to written communications from the Agency that are necessary to clarify issues regarding fee assessment (see §2105.49).