"At about / At Around" Versus "At"

[Grammarholic]

Is it unacceptable to use "at" with "about" or "around"? See below. Which is preferred, 1 or 2 in each set? I'm told placing "at" with "about" (at about OR at around) is poor form.

I write zillions of corporate reports using this format. If you had a preference, which one would you use—"about 3:15 p.m." or "at about 3:15 p.m."?

1. On January 5, 2010, about 3:15 p.m., John completed the audit ....
2. On January 5, 2010, at about 3:15 p.m., John completed the audit ....

1. On January 5, 2010, around 3:15 p.m., John completed the audit ....
2. On January 5, 2010, at around 3:15 p.m., John completed the audit ....

And is it totally incorrect to omit the word "at" and just use "about," as used in the first examples in each pair above?

Best,

gh

[Mister Micawber]

If you write zillions of corporate reports using whichever, then keep using what you have decided upon. No one has complained, I presume.
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Native English teacher at Mister Micawber's