Allow Editing of Price and Terms in Proposals Prior to Acceptance

I applied for my first PPH writing job and submitted the proposal at £65.

The client replied and said they liked my proposal but their maximum budget was £50. 

I replied to say I would do it for £50 to get a job history started and to gain a new client. 

"Brilliant" said the client.... "Thanks for being flexible,.. I'll send you the brief later". 
Meanwhile, I tried to edit the £65 price but discovered it cannot be done! Then clicked the Q & A tab to discover that PPH requires you to cancel the original proposal and then start a new one. "That's *******" I thought.

So I cancelled the proposal and then upon trying to submit a new one discovered a new message telling me it wasn't possible  "This job is not receiving proposals anymore."

I contacted the client but heard nothing back. Then noticed that the job was noted as "AWARDED",.. indicating that the client had gone with someone else.

My Point being that it is ********** to not allow freelancers to change the terms and prices of contract proposals prior to being accepted. I do this all the time with Upwork. Its a very simple process.

Why make life difficult for both client and freelancer when its completely unnecessary? It makes zero sense!

All my hard work to get my first client is now down the drain (plus one credit) all because you're system is incapable of allowing a simple pre-acceptance proposal change!