Is it legal to estimate my income in a way that causes me to overpay tax but file timely?

I'm very appreciative of everyone who pitched in, and wish to reassure everyone that I too don't find this avenue of "forcing" my EIP 3 to be a particularly attractive one, if not just because it causes logistical headaches.

To my question, though, I think the IRS wouldn't assess a penalty on my strategy. Here's what I found from researching the Internal Revenue Manual (none of this is legal advice).

• IRM 20.1.5.4.2, IRC §6662, provides an accuracy penalty of 20% of the underpayment, but I don't find any mention of a penalty on an overpayment, even an intentional one.
• Even if I'm assessed an accuracy penalty, IRM 20.1.1.3.2.2.3 provides a reasonable cause defence by the inability to obtain records that could abate the penalty in my specific case. The examiner would consider the following evidence:
  • Why the records were needed to comply.
  • Why the records were unavailable and what steps were taken to secure the records.
  • When and how the taxpayer became aware that he or she did not have the necessary records.
  • If other means were explored to secure needed information.
  • Why the taxpayer did not estimate the information. [which suggests to me that my return is supposed to estimate missing information.]
  • If the taxpayer contacted the IRS for instructions on what to do about missing information.
  • If the taxpayer promptly complied once the missing information was received.
  • Supporting documentation such as copies of letters written and responses received in an effort to get the needed information.

_{I haven't yet found anything in the IRM or IRC that would clarify the following questions, so if you do, please feel free to comment:}

• _{How persuasive is it that I file an estimate well before the deadline, or at least without requesting an extension? Grade Eh Bacon's answer alluded to this question.}
• _{Is there any instruction / IRM guidance beyond the item I bolded above that explicitly says I should estimate? Grade Eh Bacon suggests this for W-2, but how about for other forms?}