UC and CSU validation policy (other than the CPSLO oddness) effectively means that the highest level of LOTE completed defines the number of years of LOTE completed for admission purposes.
However, if the student is already above the highest level that the high school offers and does not want to take a useless high school course, then s/he may need to find some other means of showing the high level of proficiency to UC and CSU admissions (e.g. AP or SAT subject test or a few other methods are accepted).