Each Distribution rule revenue and billing calculation formula

Hi Folks,

We have following Distribution rules, can some one explain each rule revenue  and billing calculation formula or methods with suitable business examples.

If any custom calculations available specify the same(Based on your experience)

 

 

Cost/Cost	Accrue revenue and bill using the ratio of actual cost to budgeted cost (percent spent).
Cost/Event	Accrue revenue using the ratio of actual cost to budgeted cost (percent spent), and bill based on events.
Cost/Work	Accrue revenue using the ratio of actual cost to budgeted cost (percent spent), and bill as work occurs.
Event/Event	Accrue revenue and bill based on events.