Compairing Coordinates from tracked objects

Hi,

i'm currently working on my Bachelor Thesis with the Hololens and Vuforia.

I reproduce the Game Towers of Hanoi, my task is to recognize the small objects ( 5 different discs) and the programm should tell me when i move the disc to another place if the game rules (only small on big discs ) is still okay.

The recognition with the objects works fine, i scanned the objects with the vuforia app and stored them in the database and put them into my unity project in the objecttargets. 

with the DefaulttrackableEventhandler.cs file i get the real world coordinates with calling this.transform.position into my unity cubes i place holographic when ever i detect an object. 

my problem now is i want to compare the x y z coordinates from two discs to check if they are placed right. Is their any good way to do so? cause at the moment i have a lot of trouble getting meaningfull coordinates to compare.

i first check if the x coordinates is +-0.3 inline with the compared object, then the same for the z coordinate. and my plan is now to check the y coordinate if the upper one minus the lower one is negative cause the y coordinate of the higher one should be bigger. 

but thats not working always :D

if anyone finds time or has help thank you

friendly greetings.