is there ANY magnification above 100% with two monitors where a workspace capture is correct?

You mean any combination where at least one of the magnifications are above 100%?

If that is what you mean, there is one and only one of those 7 combinations where the workspace capture is correct: 125% internal magnification, 100% TV magnification:

Cannot capture region using Surface Pro4, dual monitor - extra zoomingIt should be said that the only available magnification choices are:

Internal: 100% or 125%.

External TV: 100%, 125%, 150%, 175%.

That gives 8 combinations, of which 7 are combinations where at least one of the magnifications are above 100%.