Can't set the keyboard backlight timeout on AC using stop_timeout

Hello,
the laptop is an Inspiron 15 7510. The issue I'm running into is pretty much this: https://github.com/dell/libsmbios/issues/48
meaning I can't set the keyboard backlight on AC using `/sys/class/leds/dell::kbd_backlight/stop_timeout`, except:
- I can set the value in the BIOS
- I can set the value using Dell Command configure (`/opt/dell/dcc/cctk --kbdbacklighttimeoutac=15m` for example)
- I can't set it using` smbios-keyboard-ctl --set-timeout-ac=15m`. This returns:

> Traceback (most recent call last):
File "/usr/bin/smbios-keyboard-ctl", line 713, in
sys.exit( main() )
File "/usr/bin/smbios-keyboard-ctl", line 680, in main
raise RunTimeKeyboardErr("This system doesn't support AC timeout" )
__main__.RunTimeKeyboardErr: This system doesn't support AC timeout

- The token 0x451 is absent (`smbios-token-ctl -i 0x451` returns nothing)

As per this comment https://github.com/dell/libsmbios/issues/48#issuecomment-391142780
> If you can set it from there then we are looking at a bug in the implementation of detecting AC support is available.

I'm reporting this here.
I also don't know if it's related but while fiddling with this, I've been able to use the mouse as a start_trigger (only on battery, wasn't working at first; this never worked on ac), but now it won't work again... If it's completely unrelated, please let me know so I can investigate further this different issue.