Hello,
You can add 15 minutes to the Time slider of the Daylight tool every time you press the UP or RIGHT arrow of the keyboard. But the first 15 minutes added are not shown in the tooltip right away. You have to "refresh" the tooltip to see the correct time :

When you press the LEFT or DOWN arrow, you will subtract 15 minutes. But the first subtraction will ADD another 15 minutes.
- I set the slider to zero
- I press 9 times on the UP arrow – it should be 2:15 but the tooltip shows 2:00
- I press 1 time on the DOWN arrow – it should be 2:00 but the tooltip shows 2:15
- I "refresh" the tooltip and it now shows the correct time (2:00)

Thank you !