When units are set to Pica

Create a shape, choose Object Menu > Path > Offset Path. Input a negative number and move to Miter Limit. Number changes to a positive.

Select the input field again and use arrow keys to create a negative number. Number changes to a positive.

Use a negative number from with circumstance and click okay. Object obtains an offset path equal to the positive number (not negative).

This behavior is preventing me from doing my work!