The Moroso instructions for their valve has "12V ONLY" across the top of the page. Haven't heard of anyone else having a problem though. The accumulator valve is on constant for the most part. The shift valve is only ON for a split second and have never seen any indication that 16V is a problem with them. I would call the guy who supplied it or look at their information online just to verify.

If the results don't match the theory, change the theory.