I was recently admitted in-state to Berkeley and saw that I was given a conditional undergraduate scholarship of around $20,000. I am not a regents scholar and was under the impression that UC Berkeley does not often give scholarships. On the website, it says “the amount of the scholarship award is based on your level of financial need.” My family earns an upper middle-class income, and I didn’t receive any financial aid grants beyond $5,000 for other schools – including UCs. With the current mix-ups going on with financial aid, I was wondering if this could be a mistake? Or if scholarships to Cal tend to be common? Thank you so much! 
It’s most likely a mistake unless there is something else about your background that you have not disclosed here. As a side note, I did see an incoming freshman who claims she is a resident but is being charged non-resident tuition, so perhaps there are some mistakes being made.
Cal is definitely not $15,000 more generous than other UCs.