Diference between individual and combined laser cut files

Hi to everyone i’m new to the forum, my name is mauricio and i’m really interested in beginning to recycle plastic, the only thing i still throw to the garbage. I dowloaded the blueprints of the shredder to send them to get cut it, and i found some little differences between the individual and combined files. This differences between mesures are really tiny, but having in mind that machine has to work really tight, i think that those diference can be a problem, or maybe not.
I will post one of the measures that i made, in this case will be the knife number one 5mm. The fisrt picture is the individual file where you can see the distance from the two points it’s exactly 120. Then, in the combined file you can see that the distance between the two same points, it’s a little smaller (119,8879).
So, it´s relevant this diference, assumming that the machine has to work really tight? Thanks you all for the help in advance.