Mega Backdoor Roth 401K

Mega Backdoor Roth 401K I want to confirm that I have the correct understanding of mega backdoor Roth 401K. Most of the info out there is targeted to people maxing out all the accounts, not necessarily doing what I am trying to. I have verified with my workplace 401K provider that my plan does indeed allow the mega backdoor Roth 401K (i.e. after tax dollars, in plan conversion, in service withdrawal, etc). I have the below questions: **Annual contribution amounts:** 401K contribution: $3,000 employer match: $1,500 after-tax dollars (to be "in-plan roth conversion" in my 401K): $1,000 **Questions:** I plan to take the $1,000 after-tax converted Roth out annually and put in my separate Roth IRA account (my plan allows in service withdrawal). 1. Can I still do the after-tax contribution even though I have not contributed the $24,500 limit? That seems to be the *advice* and in every MBDR example but is it *required.* 2. "Why not just contribute Roth 401K?" My understanding is that with a Roth IRA I am able to tax-free, penalty-free withdraw the contribution amount if I desperately need. But with a 401K roth, I would be subject to Pro-Rata rule and hence taxed. With a MBDR, this pro-rata rule does not apply. Is that correct? Thanks!