Because of the inability to convert proposals to invoices, we are forced to use estimates instead. We send fixed quotes, never estimates, as do most service providers, so the title of that document is misleading and confusing to the customer, perhaps even frightening since they may think this leaves the contract open for us to increase the quoted price. The word "Quote" is far better than estimate, so if anything, change it to that if you can't make it editable.
On another note, I think GHL would benefit by hiring those with experience running a service business for their design team. That may help themavoid these types of oversights.