What's up with the changing FRU numbers?

[mediasponge]

I'm refurbishing an X41 (non tablet), and I am finding something generally confusing about IBM/Lenovo FRU numbers. They seem to be changing and not getting posted to the website. I don't know if this is just on the X41, or a general issue, so posting it here for comment. Examples: The actual MB in the system is 39T5517, which is not listed in the System service parts for the X41. Same for the battery, 92P1150 in the system is not listed on the website. Even more confusing, when you buy a part, sometimes the FRU part number on the outside of the box is not the same as what's marked on the part, and neither one is listed on the website for that model! I came up with a spare battery that's exactly the same FRU, 92P1150, but the box it's in says 92P1119 on the outside. The spec says that 8-cell battery should be a 92P1149. It also appears you can't do a reverse part lookup on the Lenovo support website. You can look for it on the parts purchase section, but that only gives you a general description like 8-cell battery, or "planar FRU" which usually means motherboard.

Lenovo motto: Confusion is our most important product: it's the only thing we can ship in volume.

[RealBlackStuff]

That's nothing!
I'm trying to compile a list of all motherboards as used in T4x and R5x models.
For just this one board: 91P7186 I have found the following replacements:
91P7716
91P7186
39T5430
91P7370
91P7998
93P3512
93P3751
Have fun!

[mediasponge]

Argh!

[alkemyst]

Lenovo's 800 number will X-reference them and give you the current price.