PS CC17 artboards sizing issues

I am new to artboards in PS, but have used them extensively in Illustrator.  It would be nice if they functioned the same way.

I am trying to break large bitmaps into precise sizes for large format output, and the artboards need to overlap. Entering numeric values for artboard sizes only allows the area to transform from the upper left corner of the artboard, when in illustrator you can define the size to scale from the center or any defined edge.

is there a work around for this?

additionally, i've noticed that the info panel does not accurately work with displaying the W and H of an artboard.  has anyone else seen this?

any ideas, help would be appreciated!