Here's a couple of anecdotal transactions showing some nuances of anonymity score.

In this smaller coinjoin transaction, there were (at least) 3 different standard denominations that received anonymity score 1:

bc1pn5g6wmqs2prld00g5sp4l6837s6xt0lg27smt0zrgdlca9qdkycs3ernz8 - ‎0.00020000 BTC    
bc1pjvng7exw3d6ttu438249yasrpuprfwgc8mz6a55thxmat9hm08csgv6s0v - 0.00016384 BTC    
bc1phwkkwk6n2l75xg64wp3nsevkawzhgc9kpfs3rg99a5cghqw7mssq527s9v - 0.00013122 BTC    

So even though these standard outputs aren't "change", they are treated like change by the client due to a lack of other matches.

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Here's another rare anon score outcome I personally experienced -



I received 5 same sized outputs from a single round, so the client divided the anon score gain of each of those outputs by 5. While this seems like "waste" from the calculator's perspective, the real world effective privacy gains of allowing this sort of skew is massive.