About the 24.95mm… you are right, 0.05mm is way to small to produce this problem.
If you calculate the scale in relation to the 25mm you get an 99.8% ((24.95 * 100) / 25), the value is mostly negligible.
can you give more info about the 3d printer you are working? what type of printer, is an delta? corexy? prusa?
About the context, some months ago i receive an email to submit the printer in some type of contest, but i never submitted anything because i was sure i will not win. At the time i only uploaded the project on thingiverse, so i was pretty sure it was some type of contest promoted by them. I see on the thingivers page of the cnc you have win an contest and assumed it was the same one.