Several of us have explained the plan of salvation several times.
No they didn't. They said, in summary, and I paraphrase: "this is the plan for salvation! i'm saved! But I am still a sinner and if I become a habitual sinner then I was never saved to begin with."
Meaning that anyone who sins by some unspecified metric and the sin becomes habitual then they were never saved to begin with. In that case, OSAS can't even say who is saved since it's safe to say that we fall short of God's glory at least daily.
The Bible says you can know you're saved by who your faith is in. If someone sins they can return to God in confession, repentance, and resume fellowship.
And by the way the repentance that leads to salvation is a ONE time event in a moment in time.
It isn't.
The price for all sin is paid.
Agreed.
We can grieve the Spirit but the the status of "justified" cannot be revoked because we did nothing to earn it nor can we do anything to loose it.
You're justified by faith. Your faith is (or should be) believing what God says is true and then following those directions such as being led by the Spirit.