Landing gear mount shim problem (desperate question)

Why do the plans call for a washer (960-416) to be inserted as a shim between the landing gear mount and the 904a center section on DWG#34a? I ask because I installed said shim and then later noticed that I had pre-installed the nylon snap bushing for electrical immediately above and trapped it between the mount and the center section. Thinking that I had done this improperly and perhaps created a chafing problem for the wiring exiting the gear mount, I removed the mounts so that i could add this nylon snap bushing AFTER bolting down the mount..........BUT then i got to thinking......why this shim in the first place? Maybe I WAS supposed to insert the nylon snap bushing prior to bolting on the gear mount and that is why the shim was to be inserted below there......maybe to balance the space between the gear mount and the center section created by the insertion of the snap bushing.

BEFORE I bolt this **** thing on again, I thought that I should get a good answer from those who have gone before!!!! I just spent half a day "correcting" this problem and now I don't know if I ever had a problem at all. I checked and checked the drawings, but I can't seem to find the answer....and no photos on anyone's build sites. This is driving me nuts.

Thanks for any response!

I think that I figured this out. The shim is needed because the gear mount will not sit flush without it....and the snap bushing definitely needs to be mounted in the gear mount and not just the center section or it will not prevent chafing of any electric wires.