Marātib al-luzūm means that concomitants need not bear equally direct or equally obvious relations to their sources. Some are close and apparent; others are reached through one or more intermediate links. This permits several expressions to lead toward one intended meaning with different degrees of clarity.
“Frequent hospitality” may suggest “generosity” through a close recognized association. “Abundant ashes” can require a longer sequence: many cooking fires, much cooking, frequent guests, then generosity.
These are not fixed numerical distances for every listener. Custom, context, and the hearer's familiarity affect which steps appear easy. Nonetheless, the difference between a close and a remote concomitant explains a central feature of rhetorical indication.