I know how to blank the screen manually. I would think it would do so automatically. It does so when it is NOT plugged in.
I have more apps, but none on either phone is to change the phone's OS behavior. They are things like banking, and news. Looking at the about screen, all the version settings are identicl except for the SEPF_SM_G900V_5.0. Mine is _0013 and hers is _0002.