What is the threshold EI for Software Engineering at Cal Poly SLO?
SLO does not use EI, they use an MCA score. Also SLO calculates their CSU GPA with 9th grades but no honors points for 9th grade classes. Here is the explanation for the MCA score:
The maximum GPA they will use is 4.2, even though you can have a higher calculated CP GPA. A 4.2 is worth 2250 MCA points. Thus, multiply your CP GPA by 535.7 and you’ll get your MCA points for GPA.
The next biggest thing is test scores. The odd thing, likely because they wanted it to total a nice round number, is that the max score is 1650, even though the max SAT score is 1600. Multiply the total of your best SAT CR and your best SAT math by 1.03125 to get your MCA test points. If you took the ACT, they convert and vice versa.
The third largest section is the class rigor score, worth 750 points. In this section you get zero points for meeting the minimum admission requirements and adders for more than the minimum. The bonuses in order of power are (min semesters/max total semesters/bonus per extra semester/total possible bonus): math 6/10/125/500 (note: stats and finite do not count), lab science 4/8/50/200, English 8/10/50/100, foreign language 4/8/25/100, visual performance 2/4/25/50, no bonus points for social sciences or electives. As with GPA, you can actually score higher than the maximum, but 750 is the most they will count.
Finally, work and ECs, worth 350 points. Work (hours per week/bonus): 0/0, 1-5/20, 6-10/40, 11-15/60, 16-20/80, 21+/100, add 50 points if work is major related. ECs (hours per week/bonus): 0/0, 1-5/30, 6-10/60, 11-15/90, 16-20/120, 21+/150, add 60 points for leadership role.
There you go. Good luck. 
My D was accepted into Software Engineering on Feb. 22. My best estimate of her MCA score is 4775 (1550 SAT, 3.9 gpa, lots of work and sports/activities but not sure exactly what her hours added up to, no special case pts.) We are ecstatic!