How do you figure 4x? (presumably for frosh)
In the absence of stratified or banded admission rates by applicant characteristics, the use of raw admission rates can be misleading.
For transfer students, it looks like L&S CS and EECS are similar for admission selectivity, but L&S CS transfers need to complete the remaining CS prerequisites with a 3.3 GPA after transfer to declare the L&S CS major while EECS majors have direct admission.
https://www.universityofcalifornia.edu/infocenter/transfers-major
Possibly because many high school seniors are not that aware of entry-to-major barriers to popular majors.