nj,
it really depends on which CA schools are being discussed. If this were a private school like USD, USC, Pepperdine, Santa Clara and the like, there is no distinction on in-state against out of state tuition and costs. If they provide 25%, it is 25% of a cost certain regardless of the State of residency.
For a UC or CSU school, out of State is a major issue in terms of tuition. Out of State is more than 2X the tuition of in State. With the difference in tuition for out of State and in State, a UC, offering an out of state 25%, could be close to using 75% to almost one full scholarship for in State. Those costs plus the tremendous quantity of high quality players in CA demonstrate why there are so few out of state players on UC and CSU rosters.