So your Beginning Inventory for this year equals the Ending Inventory for last year.
BI = prior year EI
It sounds like your beginning inventory carried forward from your prior year return - if it differs from what you expect it is perhaps because you had filed an amendment or the prior year number was changed after it was filed, or the number you are expecting isn't the number that was used in the actual filing.
In any case, it should equal the ending inventory on the return that was filed last year, or the number on the last amendment that was filed for last year. If it doesn't match you should adjust it. If the prior number on the return that was filed is incorrect an amendment should be done for that year before completing this year's return.
