I would be concerned whether there could be a claim under UDAP. You advertised and enticed clients into a product and you are now moving SOME of them into a fee-based product. Discrimination? I don't know. Slippery slope? Definitely. I would consider the potential for reputational risk.
All of these issues depend on so many factors. How long has the product existed. How was it advertised. How distinct are the markets you reference. Lots of variables to consider.
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Life without Jesus is like an unsharpened pencil - it has no point.