I completely disagree that Hot Toys gets scaling right 99% of the time. Case in point is their '22 Batman.
You have to take into account, the heads should scale accordingly to what a person would look like without the layers of clothing like Joker, or the thick armor like Batman is wearing.
This is why I believe the InArt Joker sculpt is over scaled. It looks good with the jacket and everything on, but once those layers get removed it's oversized for the body.
With the Hot Toys Batman, both sculpts look way too big even with the armor on. If you were to put those on a normal body, they would look massively oversized. This was my biggest issue with the Hot Toys release was both of their sculpts' sizes. The sculpts themselves are good to the accuracy of Robert Pattinson. The sizing to the cowl on Batman and sizing to the Wayne sculpt are not right.
With the picture Godfather posted right above, I see absolutely nothing wrong with the scaling for that head. He is wearing thick protective armor and his head stayed proportional with his body underneath the suit.
Maybe I'm wrong and I can go throw on a couple big puffy coats and the size of my head will grow to stay proportional with those coats