A New York State income tax return may be filed at any time prior to the date such return is required to be filed under this Subchapter. If a New York State income tax return is filed prior to the expiration of the taxable period, it must disclose the correct amount of income and deduction to the extent known to the taxpayer at the time such return is filed, and an estimate as nearly correct as possible of those items of income which cannot be definitely ascertained at the time such return is made. If it later appears that any item of income or deduction was not accurately reported, an amended New York State income tax return must be filed on or before the final due date of such return. With regard to the income tax due on an amended New York State income tax return, see section 152.15 of this Part. Until the due date of a New York State income tax return, it is considered a tentative New York State income tax return which will then become a final New York State income tax return, unless an amended New York State income tax return is filed on or prior to such due date.