Plan B questions?

Katie
I have read from numerous sources that if you're above 165lbs, your risk of it not being effective is raised and if you're above 175, it's nearly impossible to work. Is that actually true?
Because I know while on the pill I was told it would be less effective due to my weight, but it worked perfectly fine!
**Sidenote- I will be using condoms with my partner. We are trying some new things this weekend on a getaway, lol, and I bought plan b just in case😂