Element Erase Delay
Add a field in the element options for Erase Delay. This would be a time delay before the element is erased.
As an example: I had to put a blank text element in a scene with a slow draw time as the last element so that the other text on the screen had time to be read before moving on to the next slide. I was using the Erase transition.
I tried using the delay built into the scene options, but that delay came after the transition erasure occured and before the slide actually transitioned.