Have I lost my work in iTunes Producer?

I am in the last stages of submitting my first book for the iBooks Store. I was working in iTunes Producer. I saved my work several times.

Then I clicked on a price tier, and the result was that the value became "Choose" and there was no way back to what it was before. So, I though, I close and re-open iTunes Producer. I saved my work, right? On exit it asks me save or revert? So, I check 'revert'. And I open iTunes Producer again and all my work is gone

What did 'save' do all that time?

I restarted from iBook Author, hit Save, quit. I start again, I cannot open a recent item.

Again: what does "Save" do in iTunes Producer? As far as I can see now: nothing.