According to Wikipedia on the Norwegian alphabet
The letter Å (HTML å) was introduced in Norwegian in 1917, replacing Aa or aa.
Family names may not follow modern orthography, and as such retain the digraph aa where å would be used today.
and more specifically on the subject of collation
Aa is treated like Å in alphabetical sorting, not like two adjacent letters A, meaning that while a is the first letter of the alphabet, aa is the last.
Your sort order is correct.
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