You can still contribute to your 401K while you’re on OPT or H1-B. Not sure why people are giving you grief. If you’re not selected and need to leave you can still wait till 59 or so to withdraw it or do it immediately and receive the penalty. There’s no harm to contributing to 401k even if you don’t know your long term plan.

I can’t address your original question though. I’m not an expert.