I've set the scientist and heavy scientist suits to stack (value = 10), but they still do not stack. Is this because they aren't typically lootable items?

I was not able to re-produce your heavy scientist suit stack bug / 

However, I did notice a bug between the peacekeeper scientist suit and the normal scientist suit I have patched those in the latest release.

The only way to tell these 2 suits apart is to put them on and the colors are different one is dark green one is blue. They share the same names in-game and descriptions.

Thanks for taking a look at this and patching the plugin. I'll see if I can reproduce the issue with this latest version.