Because Microsoft must always mess up and change simple things into complex one, with Windows 10 they have introduced two display off timeouts, i.e. amounts of time after which your screen is turned off:
- regular one,
- lock-off screen one.
First is set to 10 minutes (desktop PCs and laptops on AC power) or 5 minutes (laptops on battery). Second one is set to... 1 minute. Yes, every mother fucking minute after you lock-off your Windows your screen will be turned off.
And ya know, what? You can't change it! :>
Or at least, you can't change it the very easy and convenient way...
Because, to make things even worse and this fuckup even brighter, you can modify by regular means (i.e. using Control Panel) only first of these two timers. And if you want to modify the second one, you have to... mess up with Windows Registry to add missing configuration item.
Purely, the Micro-fuck-soft way. Set some important system setting to some stupid value and disallow regular users from changing it!