Form 5330 related for DB plans

My first missed 9/15 deadline for MRC in well over 20 years. I want to make sure I understand what needs to be done per my research.

Client did not make the MRC by today, around 30k

I checked 5330 and looks like it is section 4971a related. Subject to 10% penalty - not sure when needs to be paid but will instruct as soon as filed.

According to instructions, 5330 is due by 10/15 and no extension was required.

It still needs to be paid by 12/31/2025 and if not then IRS could impose penalty up to 100% for subsequent years.

I have to do interest adjustment based on the date they will make the deposit (if they will)

Am I correct on all above?

Same situation here.  Client paid 2022 (yes) contribution 10/15/23.

Which year do we file 5330 for?  I would think current year, but he did make the contribution, just only one month late.

This is first time  I have run across this.

I always mention to DB clients the diff between minimum funding and deduction.

Aren't' you late for 2022 as it was supposed to be filed by 10/15/2023 unless for 8868 was filed for 6 months extension?

The deadline from 2024 instructions, Table 1

4971 -  15th day of the 10th month after the last day of the plan year.

I am filing for my client by 10/15/2025 for 2024 deficiency on 2024 form.

Client recently sshowed a copy of his check, no way could we file by 10/15/23.

This is a one-participant plan.