That never made sense to me. If you pay $3000 interest in one year, that's $3000 in hard cahs. If you offset your tax by $3000, you would probably only have paid $300 to $600 if it wasn't offset. It's not an equivalent thing.

So you're still negative -you would effectively be paying $2400 at best in interest. Why wouldn't you count that towards one of the costs?