I assigned keystrokes option-1 to Scene style, and option-2 to Story style.
Screenshots show what the style name dropdown in the menu looks like, and then dummy text where I repeated “Scene” three times, and finally the make-up of the Scene style. The top Scene is after clicking in the work, then choosing Scene from the style picker in the toolbar. The next one shows what happens when I click in the word Scene, then do the control-1 keystroke. The last shows what happens if I highlight the word and do a control-1 keystroke.
Have tried these with other key combinations for the shortcut, but the results are always the same as shown in the screen shot.