Glad to hear back from you, Colibrí. I see what you're saying. QuickBooks allows you to add project income and expenses and assign old transactions to new projects. You can even run project-specific reports. That being said, it's important to note that you can only assign one client/customer to one project. This means that you can add different  income and expense as long as they're associated with the same customer. If you'd like to give the program a test run, I recommend signing up for a free trial on our site using this link here. Let me know if you have questions.