How do you approach bosses to let them know they’re wrong?

Asked by chelle21689 (7907) February 24th, 2021 from iPhone

More of my work problem chronicles.

At my new job I noticed some employees having both an HSA and FSA. I didn’t think you can have both unless it was a limited FSA, but we don’t offer it. I brought it to the manager and director’s attention and they were confused and said they can have both legally and that they’ve always allowed employees to use their FSA for medical expenses as well. We don’t offer a limited plan. I’ve always been taught you cannot have both unless you have a limited FSA.

I tried to do my research and all I’ve found were pages that said you can’t have both unless it’s limited FSA for dental and vision expenses. Even my previous employers practiced this. At my old job even had a way to differentiate limited FSA from a medical FSA.

I think the IRS talks more about it on p.5 here.
https://www.irs.gov/pub/irs-pdf/p969.pdf

But everywhere I looked says you can’t. What is correct? If wrong, how do I approach them again? This is a second time I’ve pointed out an error and I fear looking like I’m trying to be a smart butt and I’m going to get myself fired for rocking the boat.
I am really trying to hold on and stay here but the longer I do the more problems I see. I really need the job and it’s been hard to find one so I can’t leave.