Cavity loses its memory

Hi everyone,

I hope somebody can help me with this issue. It´s a bit annoying.

I work for the bike industry, designing bike frames.

I´m using the Cavity tool for intersecting tubes, nothing wrong with that. I like using it instead of the other (more complicated) ways of mittering.  

The tricky part is that I have many (at least 4 up to 8) different configuration for the geometry of this intersections (frame geo). So, the point is, every time I change the main geometry to a different configuration, the Cavity tool recalculates the cut but forgets which part of the cut should retain and which should delete. So I have to recheck the boxes for Body 1 instead of Body 4 or whatever is that SW chose as the correct.

To shine a light of hope, this it´s not happening ALL the time.

Any way to fix this? or to get a good reference of the part section that should save?

Thanks in advance.

SolidworksAssemblies