Windows 10: Windows 10 laptop screen dims immediately when on battery, slider can be inaccurate

I've tried looking for display settings and power options, but contrary to what I find online, the Advanced Power settings only provide an option for turning off the display after a certain time on battery, not dimming the display.There is a Brightness slider for Display settings. It is set to 47 when plugged in. If I unplug and call up the Brightness slider again, it is set to 33. I can slide it to 47 to match the plugged-in level, but that makes the slider become 67 when plugged in. There is this offset that I can't seem to get rid of.If I click on the battery icon in the Notification

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Laptop goes brighter when on battery, dim when plugged in

My dads laptop has been having this issue for a bit he says. He was having an error on boot that had an issue with the battery. And his battery couldnt hold a charge so i had him replace it. Thats all gone, but the dimming issue when plugged in is still there. I adjusted the brightness in ATI catalyst control panel but that just changed the white balance more than anything. I cant find a brightness setting in Win XP like I can in windows 7. Suggestions?

 

Windows 10 - Screen stays dim when on battery power

Windows 10 Laptop screen stays dim on battery power.

 

Dim screen Win 10?

Have read the blogs. Windows 10 needs to make it EASY for people to dim their screen. This is my 3rd Toshiba laptop and it was easy to adjust the screen on all 3 including this one, until windows 10. Will buy a new laptop without Win 10 before I'll go
through all the steps to dim screen in win 10 that is listed in the blogs I've read. I did stall an APP that helped but screen still hurts my eyes and creates a headache. Anybody have an EASY answer. It was so easy to work with DOS and windows 3.1. It's been
a pain for a lot of people ever since they came up with the REGISTRY. Thanks people.