An everyone knows, the "Elephant foot" problem can be quite well mitigated by using this setting (Initial Layer Horizontal Expansion) with a small negative value. However, the Elephant Foot effect can span more than one layer so I believe it would be a fine improvement if there was a related setting for the number of layers over which it should apply. However, rather than applying the same negative expansion value to this number of layers the value should gradually reduce over those layers. That would be more in line with how Elephant Foot appears on most actual prints.
As an example, If an expansion value of -0.04 was set, and the number of layers (proposed new option) was set to 4, then the expansion would be -0.04 for the first layer, -0.03 for the next, -0.02 for the next and 0.01 for the fourth. All following layers would be printed with zero horizontal expansion.
I think this work work very well and provide a better mitigation for the dreaded elephant foot affect.