This property (EventTextLeftIndent) is only used when CssOnly is set to false. The position of the time text is fixed and can't be changed.
The solution would be to switch to CssOnly = true and add the event elements using permanently-visible active areas:
You need to add one active area for the start (and one for the end if you wish to display it as well). You also need to shift the main text - you can do it either in the CSS or by clearing the default HTML and adding a special active area for the text at the specified position.