Businesses have some flexibility to determine their closing date rules for income and expense transactions, provided those criteria make sense and are consistent from year to year. Our rule is, "we report to the IRS what Amazon reports to us."
We use the monthly Sales Summary reports to record Amazon income and expenses in QuickBooks every month, so at the end of the year our reported income always matches the annual Summary Report.
Even though this might result in reported income that has differed from the 1099-K by about $50 for every $100,000 in income, our tax forms always exactly match the annual Summary Report - so they should be much easier to defend in the event of an audit.
It doesn't seem efficient to adjust your books for every deferred transaction, since any transaction not appearing in one period will appear in the next, and the IRS gets paid either way.
We also don't make those ad-hoc 'deferred transaction' adjustments to our books because this would be error-prone – and much more difficult to document in the event of an IRS audit.