MaxHeadSize Inoperable in R2017a for Quiver3

I'm trying to change the arrow head size for a quiver3 plot. I'm using R2017a. 'MaxHeadSize' doesn't seem to change it though.

I pulled this sample code from the Matlab Help:

x = -3:0.5:3;
y = -3:0.5:3;
[X,Y] = meshgrid(x, y);
Z = Y.^2 - X.^2;
[U,V,W] = surfnorm(Z);
figure
quiver3(Z,U,V,W,'MaxHeadSize',0.5)

Help says 0.2 is the default head size. However, no matter what I change it to in my code, the outcome appears the same.

Any thoughts?

Thanks in advance!

M Ridzon