single entry date - how does it work?

I've got the EOB in front of me (both hardcopy AND online) and this still makes no sense.

I took over a plan that says eligibility is no age, 6 months with 500 hours (reverts to YOS if not satisfied), entry date is January 1 following satisfaction.   What?*

EOB says that there is a way to design the plan so that this is OK, and it discusses using more-lenient-than-statutory requirements, which is what I've got.  But the example shows someone hired in the first half of the year with 6 month eligibility - that's the easy situation!  So if I'm hired in June 2024, I'm eligible 1/1/25, and if I'm hired in July 2024, I'm eligible 1/1/26.  People hired in the second half of the year are getting the shaft, right?

What am I missing here?  Why does this look so shady?  And, more importantly, is this plan OK as is (the prior TPA has done other questionable things, so I'm not taking anything they produced as good unless I can prove it)?  Is there something that explains is differently that I can check out?

Thanks.

* I love that, 30 years in, I still find things I've never seen before.  Yeah, "love"...

Yes it meets the the requirement by making a single entry date on the first day of the Plan year and no one is kept out more than 18 months which is acceptable.

Yes folks hired in June have the shortest 6+ month eligibility, May 7+ months, April 8+,....,Dec 12+ months, ... July 17+months

Thanks.  I was mis-remembering how the maximum worked.  I thought it was six months after meeting the elig criteria.

A lot of pension plans had a 20 1/2, 6 months, single entry date design so they could deal with (and value) new entrants all at once.

However, I thought that was a straight 6-month elapsed time requirement and you could not attach any hours requirement. Say your June 2024 hire only worked 490 hours. You don't put them in at 1/1/2025, you look at 2025 hours for YOS and possible entry 1/1/2026? That makes me a little nervous, interested if others are fine with that. What is that subsequent YOS requirement, 500 hours, 1000 hours? If 1000, that makes me more nervous.

It's 1,000.  I don't like this whole concept, so as part of our takeover-restatement, I'm going to tell them that they have to change it.  They've never had more than four employees - I can't imagine this is a significant issue for them.

It works poorly.  That's what I would say.