Many of us use a few 'cones occasionally, and you don't necessarily have to use sulfates to remove them - most can be removed with coco betaine or other surfactants. Maybe this will help you:
www.naturallycurly.com/curlreading/curl-products/whats-the-scoop-on-silicones
I don't know what sort of surfactants Wen contains, but if they also use silicones, I'd guess it's something that removes 'cones - at least the ones they use in their own products.
I personally don't care for much in the Deva line, and I've never tried Wen - too much other stuff that has better ingredients for less money