The Asian bucket was better performing even before the latest wave of immigration. However, supposedly that declines with each generation such that by the 3rd generation, there isn’t much of a difference. Perhaps regression to mean?
The buckets are defined by the US federal government [1], and then get used by educational institutions and employers as checkboxes on forms whose answers are used to compute diversity statistics. And the US federal government's "Asian" bucket is defined as "A person having origins in any of the original peoples of the Far East, Southeast Asia, or the Indian subcontinent including, for example, Cambodia, China, India, Japan, Korea, Malaysia, Pakistan, the Philippine Islands, Thailand, and Vietnam". So that definition does explicitly include Thais and Filipinos
[1] https://www.census.gov/topics/population/race/about.html
You think, if Yale publishes these statistics on their website, that Yale’s admissions officers aren’t thinking about them during the admissions process?
Harvard
Tap on SAT by Ethnicity
Look at Pacific Islander vs Asian. That is as close as I have found so far.
Prior to 1997, the US government had a single bucket, "Asian or Pacific Islander". Since 1997, they've been split into two separate buckets (although it took some time for the bureaucracy to fully adopt the new grouping – the 2000 census still used the old classification, but the 2010 census adopted the new one.)
[1] https://www.census.gov/topics/population/race/about.html
In the current system, you're essentially punished if you're Asian, but what is "Asian," really?
Chinese, Japanese, and Koreans often immigrate to America with advanced degrees, wealth, etc. and they pass those advantages on to their kids, hence the high standardized tests scores / GPAs, but immigrants from Thailand, Vietnam, and the Philippines often come here with nothing in search of a better life, and their children are tossed into the same "Asian" bucket, and punished.
Maybe you could have one "non-white" checkbox that would award you a few points to partially offset any historical exclusion of nonwhite people in the university, which is important if they still have legacy admissions. Hispanic people might not have the option of getting extra points for having a father that went to Yale, who himself had a father that went to Yale, if Hispanic people were outright excluded in the past.
I think we'll eventually move to something close to what you're describing. You could get some points if your parents are poor, or didn't attend college themselves, or don't speak English, but categorizing people into one of a few crudely drawn racial categories has got to end.