Iterations and limit with Calc

With the first spreadsheets I remember the main idea behind iterations
and change limit was consistency within spreadsheets.
It seems this has changed.
When cells were changed within the set limit the iteration marker was set.
For iterations it was compared and when the number of iterations was not
reached the whole sheet was reprocessed.
Why has this changed to a cell iteration value where the number of
iterations is processed on a cell basis?
Can it be expected that this will be changed again in the future?