Spotting and soap behavior are preference clues, not proof that a softener will solve every taste, odor, corrosion, or appliance problem.
IWVWD's current report shows a range of hardness results and describes hardness as a quality issue. Ask a seller to use your actual result and explain how the proposed treatment changes calcium and magnesium, what it does not remove, and how performance will be verified.
Keep this boundary: A generic free water test tied to one product is not the same as an independent drinking-water safety assessment.