I've used the Leon kits with the width matched grill and a Snap Razor arm. My opinion is it makes the TV look better, especially larger TVs. Playbar looks goofy by itself under a 55 or larger TV.

I look at pricing a little differently. I start the client conversations with a picture of a finished installed showing a width matched grill under the TV. That's usually enough to justify the added expense over and above the TV. If however I were to get push back I might explain the mount not only makes the finished product better but will save them money. All the dicking around with either the universal brackets or fabricating a one-off could add up to a couple hours of time if you track it accurately.