Hi guys; I'm trying to make two pockets (Slots really) in a piece of .375 material. The "outer" slot is .250 deep and then the "inner"  slot goes through the material. To save some moves I tried setting the "Start Cut" of the inner slot to -.250 after the outer has been routed. As you can see in the attached screenshot LC acts like it Start Cut parameter is always a positive value. Setting Start Cut to 0 produces the expected result. 
Have a good one.