spacer question in 76mm refractor

I have a question regarding my vintage tasco 10te. When I originally purchased the scope a few years back I noticed that one of the spacers was not made of the same material as the other 2. 2 of them looked like metal or tin foil, but the 3rd one was thinner and looked more like paper. I also noticed a bit of coma so I thought well maybe I should replace the one spacer with something more similar to the other metal looking spacers. I couldnt really find anything the same thickness, so I used stamp material for all three and tried varying thicknesses. The coma seemed to only get worse or stay the same. So then I thought why not just try and remove the one spacer and keep the other 2 in their current positions. Well, the coma is almost all the way gone and the little bit of color I was seeing seems to have improved as well. So my question is, why are the lenses performing better with that spacer gone?
Thanks
Martin

Likely there exists what is termed Wedge with respect to one of the two elements. IOW one element was produced at a slight angle to the optical axis. Unequal original spacers attempted to correct this example anomoly by tilting one element with respect to the other thus aligning the optical axes of both elements. Of course, without that 3rd spacer (of appropriate thickness) the two elements could now *rock* on the axis of the remaining two spacers upsetting their alignment, or worse rest glass-to-glass at that 3rd spacer position risking damage to the rear elements' softer surface. So, replacing that 3rd spacer as originally assembled is recommended. Rotating one lens element with respect to the other also alters wedge effects & performance in general, so ALWAYS apply index marks to the edges of both lens elements for same prior alignment when reassembling. At this point, you'll need to make several trials with different element rotations (respective to each other) to discover the correct alignment with 3 spacers. Use temporary lead pencil index marks until satisfied, then index mark with a permanent felt tip marker.