that shooting time with 60 seconds between shots was about 2.5x longer than the shooting time with 4 seconds between shots.
Really?
I have done measurements on S110 with set_backlight and set_lcd_display.
Shooting Mode 0.44A
Shooting mode + set_backlight (0) 0,40A
Shooting mode + set_lcd_display (0) 0.38A
Shooting mode + set_backlight (0) + set_lcd_display (0) 0.36A
So, you can save around 20% on S110 with the display.
I could not see much differences on shooting mode (Continuous, single mode).
Yes of course, focus and IS needs energy but I have always switched IS off and focus is locked.
And I never checked switching to Playback Mode between shots.