Tracking Income & Expense per Service, Client, Project

[Lou]

I want to track income & expenses per service, per client & per project 
for my business.  I'd like to know how you all have done this.  
Currently, to track income per service I have created:

Income:Sales:Service 1
Income:Sales:Service 2
Income:Sales:Service 3

Is this the best route?

My understanding is that I can use the jobs function to track income per 
client.  This works fine for tracking income per service & I once I 
start using jobs, then I can track income per client.

Now, the problem is that I want to track profit per client, per service, 
per project.  However, I don't see a way to track expenses per client, 
per service, per project.

Can anyone help with this?

Thanks,

Lou