First a clarification:
Mary Lou Frost wrote:
Well, I have known for some time that when an image is sized by pixel dimensions it doesn't matter how that is expressed in resolution…
It is impossible to express image dimensions in terms of resolution (ppi).
That would be like saying that you can express a person's age in terms of how much that person weighs. Patent nonsense.
Mary Lou Frost wrote:
…It came as a surprise to discover that the resolution does make a difference when using the type tool.
Why is that true?…
Apples and oranges.
In the discussion above, we were talking about resizing a pixel image. Your text is in vectors, on a different layer or layers.
If you flattened your image before resizing, you would not see a difference.
The sensible solution, of course, is to create your text only after resizing your pixel image. That would be the logical workflow.