"Aspects to Planets" Calculations

Hullo friends - I've just started my journey in the world of Kala and had a question. In using Kala Software -> Aspects to Planets Table, how does the software calculate the +ve and the -ve points seen in the bottom two rows? 

For example, in the screen shot attached:

In the first "Su" column, Sun is aspected by Moon with 50 points and aspected by Jupiter with 59 points. Sun and Moon are not enemies yet the bottom shows as (-50). Why is this negative when the two planets are not enemies as such? FYI Moon is in Scorpio in this birth chart.  

Sorry if this is a basic question - am just starting the journey. Thank you.