How different between accrue revenue by expenditure item and by events?

Hi,

I use the distribution rule Cost/Event for my project. If my project has multiple agreement with hard limit and only the first agreement is not enough for funding. When I generate draft revenue, the result is error and the rejection is hard limit. I see in the Project billing user's guide on page 5-31 that 'If Oracle Projects cannot find enough funding for the full potential revenue amount, it creates partial revenue for the expenditure items.'

If the revenue can create normally, the event will be create automatically for this case. Is it mean that thiis is accrue revenue by event? If yes, how can I change to accrue revenue by expenditure item to create partial revenue.