[1.0.8] Stackable bonuses inconsistent

[fbo]

The property "Stackable bonus mult" works differently for e.g. a traders wooden backback and a general storage chest: While the latter correctly uses the items "stackable" property the former does not. I assume it's related to the backpacks additional property "stackable bonus minimum" which is used in the multiplication instead of the items "stackable".
This effectively caps every stacks size in the backpack at 9 while the stack size in a general storage chest differs with the items "stackable" (In an unmodded game this effect should be reproducible with armour plates).

I don't believe it is intended to have different calculations for the same concept. "stackable bonus minimum" is unnecessary and probably just legacy code.