550i Rotor Life question

I need to replace my front pads on my 2007 550i. My thanks to many on here that have given recommendations on pads, rotors etc.

I wanted to determine if my rotors also needed replacement. I know they replaced both pads and rotors at 50k. The car is now at 77k.

The stock rotors are 30mm or so and I believe the minimum thickness is 22.4mm

I just measured both my front rotors with a set of calipers and got approx 27-27.5mm. So lets say 27mm.

This makes sense to me as I believe the 50k new set of rotors were this cars first new rotors, so they lasted 50k miles. I am only 27k into this set and if the next pads last about the same, I am close to 50k and the rotors would be down to 23-24mm...which would need to be replaced.

Therefore, I have determined that I only need to replace the pads.

Does this make sense to those that have done pad changes and DIY changes?

thanks

Upon further investigation, I see in the BMW TIS and on various other websites that the min thickness is actually 28.4mm . The 22.4mm I noted prior was for a 525i, not a 550i.

Which tells me I need new rotors.

Can someone concur?