Brian Manzella's ignorance regarding a DH-Hand release action
Watch this Instagram video featuring Brian Manzella.
http://instagram.com/p/CnVCFyHKSX0
In that video BM discusses what one should do with the wrists through impact.
BM believes that the lead hand should rotate counterclockwise secondary to lead
forearm supination while the trail forearm pronates so that the trail hand can
roll over the lead hand after impact (representing what is called a "release
swivel action) - and BM poses at the P8.5 position showing the completion of his
release swivel action.
Here is a capture image from that video of BM showing that P8.5 position.

BM categorically states that all great pro golfers throughout the history of pro
golf look like this at the P8.5 position when they are halfway through their
followthrough action.
I would agree with BM that the majority of pro golfers will use a release swivel action in their later followthrough after P7.5 if they want to get the clubshaft to lie on the swingplane where the butt end of the club often points at the ball-target line (indicating that their clubshaft is on-plane) at the P8.5 position.
However, there are two ways to get to that P8.5 position - where the trail forearm's pronatory action has rolled the trail palm over a supinating left hand.
The one way is to start the release swivel action immediately after P7 so that the release swivel action is completed early before P8.
Here are capture images of BM demonstrating that type of
rolling subtype
of non-DH hand release action through impact.

Image 1 is at P6.8 - note that the back of BM's lead hand (glove logo) is still visible immediately pre-impact.
Image 2 at P7.2 shows how much his lead hand has rotated counterclockwise through impact secondary to a lead forearm supinatory motion while his trail palm is starting to rotate over the top of the club handle, and that represents the start of his release swivel action, which causes the clubshaft to bypass his lead arm (from an angular rotational perspective) by P7.2.
Image 3 shows that BM has completed his release swivel action by P8.
However, many pro golfers do not perform a release swivel action between P7 => P7.5 and they delay it so that it only happens between P7.5 => P8.5.
Here is an example - featuring Justin Thomas.