Extra step?

[bownarra]

More nodes means more little stiff spots along the limb. Better to keep things even limb to limb. Another reason to splice boo backings is if you have one that isn't straight. Sometimes they can be cut and then spliced straight. I tend to use most of my lower quality boo like this.
The closer you get to gluing up a pre 'tillered' lam bow the more these things matter as well.
I prefer a z-splice for boo backings as you violate the fibers less.
As for your powerlam it is unnecessary in this style of bow (belly wood is plenty thick).

[leonwood]

I agree that it looks better with evenly spaced nodes on both limbs although I have never had any issues with uneven spaced nodes and stiff spots in bamboo. (I do make my bamboo backings as thin as possible though)
Also I don't think you need the powerlam at all, however you can speed that part up by glueing the powerlam with ca glue, that way you can continue in an hour or so.
And for the fun of it, I even glued a v-splice with ca glue when I did not have any epoxy left. On a 56 pound bow without any problems