I am a bit confused as I was under the impression that the Sales Orders module which is still being worked on would be managing the project profits.
See post - Status of quotes, Sales Orders and Purchase Orders Idea - #18 by Abeiku
and post Status of quotes, Sales Orders and Purchase Orders Idea - #19 by lubos
and post Status of quotes, Sales Orders and Purchase Orders Idea - #20 by abdulbari
and lastly post Status of quotes, Sales Orders and Purchase Orders Idea - #21 by lubos
I think it makes more sense to use the Sales order as the module for managing the project as presumably everything for the project would be in this Sales Order.
Then you not only have the Progress of the order, what’s invoiced, Order Status and amount, delivery dates etc as shown in @Abeiku example in the first linked post.
I am pleased that you are implementing the Project Based Accounting, but from my limited understanding of what was said in the above linked posts and also the fact that most of the information is already in the sales order, I am not sure why you see it as more logical to have a separate tab for this?
I would think linking the purchase invoices and sales invoices to that sales order would basically do all the work calculating the project profits for that project. Is that not easier?