Is it okay to revise in the middle of a project.

Finding your own way of working can take time - try it, there is very little in writing that is unfixable. If revising proves detrimental then you can always just begin the story again - most things can be fixed and worked on.

Personally I don't need to revise even major changes, I just change it midflow then go back and rewrite it in the right order.

 

what does that mean?

 

Well in comic books it means "that reason we were working with back in the '60s was stupid, this is how it really works."

Retroactive Continuity.

The way I'm trying to (hamhandedly) use it is to say that something that happened in the manuscript didn't happen, assume it didn't happen when writing out the rest, then go back in the editing process and fix it so that it never happened in the story.