SAI and Included Angle

So I have had an alignment done on my Prius. My vehicle has out-of-spec SAI. It is listed as 20.2° front-left and 22.8° front-right, for cross SAI of -2.6°. This also naturally results in out-of-spec Included Angle as well.

My question: My Prius is up to nearly 165,000 miles on original suspension components. When I google SAI problems, every results seems to point to "something is bent, go get it fixed!" I was wondering if this can also be cause by severely worn suspension components - and if so, what?

There is a specialty wheel/tire shop in town (this is a reading from NTB, a chain store) that appears likely to have better staff and experience, which I am considering visiting. Is this advisable? The NTB tech had no advice other than "we can't adjust that, maybe ask your dealership."

Also, I have two readings for my left-rear from separate alignments, showing 0.51° Toe (previous alignment) and 0.37° Toe (today's alignment) - also falling under "non-adjustable." I understand this is likely a matter for a shim-kit, provided I can get a trustworthy reading on the angle there. Are there any recommendations for this?