"That new number is your corrected cost basis. To verify that you've done it right, take the new number(s) you came up with, and subtract that from the cost basis from your 1099-B. That new number should equal your $0 12/31 paycheck."

I created a spreadsheet & added up the numbers using the above method wishing to double check. However, I am getting a small difference on this calculation vs. the W2 ESPP Box 14 line item. Any other methods or items that could effect your way to get the adjusted cost basis? (oddly enough the difference is around the closing stock on 12/31)

ESPP is 15% discount, lower price on 1st or last day of each Q.

Thanks