Intro and help on distance between PCI bracket and motherboard edge?

Hey all,

I'm an electrical engineer currently working on a custom micro-atx PC case. I want to make my own one-off case because I haven not found a solution for the build I had in mind on the market.

During my research and mock-up phase, I ran into some conflicting info on the distance between the PCI bracket of a card and the edge of the motherboard.

Using the models for the micro-ATX board from the Resources page ( ) I am measuring a distance of 1.95mm between the edge of the motherboard and the PCI bracket:

However, looking at the .DXF files posted on Protocase I see that the "recommended" distance between the front of the PCI bracket and motherboard edge is 1.14:

Does the ~1mm difference here matter in the real world? If so, which one is correct? I am asking because I have been using measurements from the Protocase .DXF files for sizing my case and when I placed the micro-atx board in the assembly, I had the PCI bracket colluding with my I/O panel. Image of that is below: the distance between the inside enclosure and board edge here is 1.7mm, as shown on the Protocase .DXF. You can see the PCI bracket highlighted in orange at the top of the screen clipping inside of the back I/O panel. If I increase the 1.7mm distance to around 2mm, no more clipping occurs and I am pretty sure that at the end of the day it won't really matter, but I'd rather know exactly why I am running into this issue.