Better track review based on a *when* the revenue was generated vs. when it was billed

Better track review based on a *when* the revenue was generated vs. when it was billed

I love Zoho Books. I just have a problem with the way revenue is being reported in my company's Zoho Books subscription.

We have a professional services firm where we bill clients based on timesheets.

We have dozens of clients, each with different billing requirements. Some clients are ok with being billed monthly - others want to be billed quarterly. There are also instances where we'll differ billing a client for many reasons. 

As far as WIP is concerned, we have a lot of revenue to be billed. But, you don't see that because, at the moment, all we see in the Zoho Books expenses vs revenue charts is *invoiced* time. I want to see the un-invoiced revenue so that I have an idea of what my potential revenue will look like in the coming months.

Additionally, I would like to run a report showing me revenue vs expenses based on when the revenue was generated by the timesheet entry, not based on when that timesheet entry was ultimately invoiced. So, for example, I have an invoice dated March 31, based on timesheets between Jan-March. In April, I want to run a report showing expenses vs revenue for Jan, which should include the revenue generated by the Jan timesheet entries (even though they weren't billed until March).

Hopefully this makes sense... I thought I would post it on here as I figured many people have a similar requirement.