I've seen various references to "periods of adjustment" in Protestant theology too. The idea isn't that of paying for a guilt (which only Christ can do) but of continuing to grow in grace -- in the presence of the Lord. Coming to final repudiation of all one's past sinfulness would be part of it, which is brief. As I grow older and sin less, yet ironically I see my remaining sin better and better, and then part with it better and better. Some of that sin is in self agonizing doubts that the Lord could or would show sufficient mercy, like He would say "well, you didn't get perfect on earth, so I'm going to send you to the eternal scrap heap." What kind of hope could be based on THAT? But then when I go to relief of the everlasting arms, it seems strange at first. Until I realize that it's just a place to rest, not a place to carry on.
and that is the concept of purgatory - part of the purification process.
like He would say "well, you didn't get perfect on earth, so I'm going to send you to the eternal scrap heap." - but He won't. He will purify you. You can't save yourself, but you must be completely sinless in heaven, so god purifies you.