Simple draft analysis help

Here is a picture of the part I am trying to do draft analysis on....  This is cast using a match plate, so you can see that it is essentially split down the middle, perpendicular to  axis 1.   I know that I can work around this issue and "make it work", but I don't understand why I can't get the draft analysis to work in the direction I want.

It works in the perpendicular direction when I choose the round face...

but that is not how this part would be split......

I am trying to split this right down the middle.  I projected a parting line onto the surface... that didn't work either. 

so...  I wacked off part of my part to make a face for the direction of pull... and it works.

Isn't there a way to define the direction of pull on a part like this without have to make a face?

For some reason... this just doesn't work in my SW2015.  I made another simple test to see if I can get draft analysis to work by using a plane for direction of pull... the plane turns pink or purple, but draft analysis will not work.

If I extrude cut a flat surface on the top...... it works....

This is driving me nuts!

I am new to SW....  I purchased this for the sole purpose of designing patterns for our foundry.  So I am a little perplexed on how to move forward.....  So far. I have found 2 ways to manipulate it to work, both are not ideal.  The first, is to add a planar feature to the part,  this is just stupid.  The second is to add a cube or some other feature not connected to the part.  This doesn't affect the part itself, but you can't use parting line analysis because you have to choose the actual body you want to run the analysis on.    So am I correct in saying that SW2015 has a serious problem if you intend to use the Mold Tools?