OutLines

Just need to make sure this is actually what is happening.

If I was to have a circle drawn with a "line" and this line is "4pt" in width. Now if I put an "Outline" around this circle with another "4pt" line, coreldraw places that outline with the "center" of the outline on the outside edge of the circle, thus making the combined width of both now "6pt" because 2pt's of the width of the outline is actually under the circle line.

This is why I ask. I design artwork for t-shirt and everytime I have place an outline around my image and sent it off to the printer it always comes back with my outline being about half of what I expected it to be.

Is this correct? 

Thanks David