If 3u and 4u both count, you'd actually need ~98 in english, eco and modern.
Hsc ninja overestimates top atars (it says an aggregate of 468 is enough for 99.95, when ~478 has been needed for the past two years).
at grammar, most 99+ come from non-scholarships as @dasfas said (also there are ~50 99+ per year now)
fun fact: of the top 20 at grammar in my yr, only 5 were on scholarships (and only 3 were academic scholars)
grammar is def an exception though; at most other private schools, top atars...