Tub/shower valve rough-in question

I'm about to rough in the Moen valve for my tub/shower (model 2520). The instructions from the Moen site indicate a max distance of 11" between the valve and the nipple for the tub spout. That would put the valve and resulting shower control at somewhere around 32" from the floor. While I understand this is the preferred height for a tub/shower combo, I would prefer to mount the valve higher since I never use the bathtub, only the shower. I'd rather not have to bend down so far to turn the water on every day.

Is there a reason why Moen lists the max distance as 11"? I don't understand why this distance can't be whatever I want it to be, since it's just a pipe connected to the valve and running down to an elbow. It seems like the distance wouldn't affect the performance in any way.

Is there some factor I'm missing here? Can I mount the valve higher on the wall and go with a longer distance between the valve and tub spout?

As a side question, how far off of the top of the tub does the spout normally get mounted? The centerpoint of the tile it will sit on is 6.5". Is that too far up?

Thanks.
Mark

It is possible for the increased length of the spout drop to add enough friction that you will get water out the shower head when the tub is filling.

valve

That Moen dimension is a CYA approximation. Use it and they do not have to worry about you calling them because the shower also drips when you use the tub. As a practical matter you can use a longer dimension. My spout is a "toe tester" in the shower and it is 30" below the valve and everything works as it is supposed to, as does my other shower also. Just do not use PEX or any plastic tubing between the valve and the spout.

Thanks guys. I wanted to put the spout about 20" on-center below the valve, depending on the spout height, so it sounds like I could be okay. Connections will be all copper. Other opinions are welcome though.

About the spout, is 6 1/2" above the tub too high?