Waxed chain poor shifting

So I recently tried waxing my chains doing the procedure described by moltenspeedwax. Not too much of an hassle. The drivetrain runs super silent, but it seems that shifting to smaller cogs in the back doesn't always work super smoothly, while going up the cassette doesn't seem to be problematic.
I've observed this on both my road and mountain bikes. Both were shifting flawlessly prior to switching to wax. Has anyone had similar issues with wax?