It's not necessarily the case that the box should be checked. If you began employment (or otherwise began participation in the 401(k) plan) with this employer in 2021 and the 401(k) plan uses a fiscal year instead of a calendar year, it's possible that your participation during 2021 makes you covered for 2022 but not 2021. You'll need to ask the employer the end date of the plan's year and if box 13 Retirement plan is correct or not. You are covered for the calendar year in which the plan year for which additions were made ends.
