Analemma's disprove your claim. You can capture an annalema by taking a picture of the sun at one location, every 24 hours, for a whole year. The sun will produce a figure 8 pattern. This will cause the shadow on a sun dial to vary a miniscule amount through the seasons. This is not enough to throw off a sun dial for practical purposes. Ideally you would align the dial to somewhere in the middle of the annalemma.
In the globe demonstration above it looks like spring and fall would have the shadow cast at about a 45+ degree angle difference. Sun dials don't have to be adjusted once you set them up. Some ancient sundials haven't moved in thousands of years.
Analemma's disprove your claim. You can capture an annalema by taking a picture of the sun at one location, every 24 hours, for a whole year. The sun will produce a figure 8 pattern. This will cause the shadow on a sun dial to vary a miniscule amount through the seasons. This is not enough to throw off a sun dial for practical purposes. Ideally you would align the dial to somewhere in the middle of the annalemma.
In the globe demonstration above it looks like spring and fall would have the shadow cast at about a 45 degree angle difference. Sun dials don't have to be adjusted once you set them up. Some ancient sundials haven't moved in thousands of years.