Pathfinder: Minus-front - unwanted slimming effect

Hello,  

Goal: I trying to use minus-front to create a single-color design for a t-shirt print project. The shirt color will be green. In my design, the green items are the front items that I want to 'knock-out'.

Issue: performing minus-front slims the knockout. My image and text become thinner. (See attached A/B examples). Yes, it's slight, but I don't want slimmer. What's going wrong?

Specifics: In both cases, the green layer has no stroke, is outline/no longer font in the case of the text, and is a compound path. The black layer that I'm trying to knock thru also has no stroke and is a compound path. There are no active appearance effects on the layers.

Further: I've 'minus-front'ed other objects on this design with no noticeable problem. Is it possible that because other items were bigger the slimming effect was less noticeable? Or is there a solution?

Thanks in advance!