Lacerte software tells me a corporation return with a year that ends 9-30-2021 has a due date of 12-15-2021.

The IRS instructions say a corporation with a fiscal year, other than 6-30-xx, has a due date date of 4 months and 15 days from the end on the fiscal year.

Do I believe Lacerte (12-15-2021) or the IRS instructions (1-15-2022)?