I believe when you manual lock the screen power buttonRight, and that setting is only for how long it takes for the phone to lock after the screen turns off.
If power saving mode is on it can shorten what ever it's at, for example if you choose from that screen 1 minute that means it will not lock which ask to fingerprint or password/pin until that time out metBut it doesn't affect how long the lockscreen stays on, which I don't think can be adjusted manually. I think some phones will shorten that duration even more if a power-saving mode is turned on.