The "expert" Chris H is CORRECT.
The relevant passage from Publication 463 is:
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Exception. Documentary evidence is not needed if any of the following conditions apply.
You have meals or lodging expenses while traveling away from home for which you account to your employer under an accountable plan, and you use a per diem allowance method that includes meals and/or lodging. ( Accountable plans and per diem allowances are discussed in chapter 6.)
Your expense, other than lodging, is less than $75.
You have a transportation expense for which a receipt is not readily available.
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