Does having more towers built on map affect loot quality (negatively)? I followed this guide to obtain my first mythical gear. The first time I succeeded I think I only had 4-5 critical towers placed on map and I got mythical gear from all 4 chests. Now that I'm stronger, I am able to build 9 critical towers by the end of the wave and I often get 0-1 mythical items.
Does this happen by pure chance or should I sell some towers just before the wave ends?