You’ve clearly never interacted with a regulator before. When a regulator send you a letter with difficult questions, there is an extremely strong implication that a failure to answer those questions correctly will lead to more difficult questions, and, undoubtedly, official investigations.

You don’t want an official investigation, they are a complete nightmare that eat up months of work hours. Much better to spend a couple of days making sure you can give the correct answers on the first pass. Unless of course you genuinely believe the regulators are pushing beyond their remit, but know you’re voluntary signing up for an expensive and protracted fight.