Difference between real lifes distance and packaged\editor distance

Has anyone experienced a difference between real-life distance and in-headset distance?
I have made a 3-meter wall in 3ds max and exported it to Unreal via Datasmith and I’m 100% sure that the dimensions are accurate in Max. In the headset, if I stand at one end of the wall and walked in real life to the other end, measured the distance I walked in real life, and compared it to the wall length, there would be about 10cm or more difference (3m in Unreal would be 3.10 or more in real life).

I’m using it for ArchViz, so dimensions are very important to be accurate.
Any Idea about why is this happening?