How well does collegevine take major into account?

I understand this website is algorithm based and it won't be 100 percent accurate. I am applying to be a computer science major and have been extremely stressed out about whether I'll get accepted into the schools I want. Collegevine is saying that I have a 95% chance at Minnesota Twin Cities, an 83% at Wisconsin Madison, 80% chance at Virginia Tech, etc. I feel that these numbers would be correct IF it was talking about general admissions without majors being considered, but these schools for Comp Sci are extremely competitive and I can't wrap my head around the fact that my chances are so high for schools that have under a 20% chance of admittance.