Today, if you - when producing a preliminary sales invoice - find that you need to move time transactions from one project to another, you have to go to the project plan and make the move. You should be able to do this also when handling the preliminary sales invoice, avoiding to have to go between the project plan and the exiting the preliminary sales invoice process.
To reduce time to manage this. Currently, you have to exit the preliminary sales invoice and go to the project plan in order to move transactions between projects. This would make it more efficient.