-If you select "send invoice" on the estimate screen, once the estimate is approved, the system changes the estimate to an invoice. In doing so, you can now no longer download the estimate PDF at all. why?

-If an estimate is marked as approved, and the "send invoice" option was clicked, you can not go back and unapprove it.

For example, an estimate was mistakenly approved, and then the customer got the invoice request immediately and there is no way to go backwards and unmark it as approved. Why?

It's confusing to my users why the access to things change, and why actions are not able to go backwards. Can someone explain what the use case is for this situation of limitations?

What would be ideal

-you can download a pdf of an estimate if it's sent or approved

-you can download a pdf of the estimate even after it's converted to an invoice

-you can always go backwards and undo an approval of an estimate or remove an invoice

-there should be more clarification, warnings on the "send invoice" button in the estimates so that you know exactly what will happen and what is and is not changable moving forward.