Screen scaling - a 1280x1024 Customer screen is not showing correctly on a 1920x1080 screen

Screen scaling a great feature - leaves some mixed feelings. On the bright side - it works. But not exactly as I would expect.
(The same applies to "GoToAssist".)
a) My Customer Server screen resolution is set to 1280x1024. On my Agent PC resolution is set to 1920x1080 both monitors are widescreen 9:16.
If I select a "100%" magnification - the Client 1280x1024 image do not fit my Agent PC using the 1920x1080 resolution?
"Fit" - seem to scale image to 100% (by the pixel count).
b) My Customer Server screen resolution is set to 1600x1200 (3:4). On my Agent PC resolution is set to 1920x1080 both monitors are widescreen 9:16.
If I select a "100%" magnification - the resulting image that should(?) be 1600 pixels wide do not fit and wider  1920 pixels resolution screen on the Agent's PC?
-- Yes, scaling works. But using its own logic.

On the Bright side - scaling helps when we need dial into the third Computer from the Customer Computer.
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