Question

Will it change the color of my roof?

A treated roof usually goes back to looking darker and more even, closer to how it looked when it was newer. That is the oil returning to the shingle, not paint.

It is not a coating and it does not recolor a roof. If someone offers to spray your shingles a new color, that is a different product with different consequences.

What you see in the first few days is the treatment settling. A freshly treated roof looks darker while the oil is still working into the shingle, and it evens out from there. The difference is easier to judge from the street than from a ladder.

Slopes that dried out fastest usually show the biggest change. A south or west face takes more sun through a Utah summer than a shaded north face, so the two can end up looking further apart than they did before, not closer.

If matching matters to you, raise it at the inspection. Every slope is photographed before anything is applied, so you can hold the after against the before rather than against memory.