Reparation for Misuse of YHWH's Holy Things
Here the Christological path is unusually concrete: Leviticus names the asham reparation offering; Isaiah later says the Servant becomes an asham; the New Testament identifies Isaiah's Servant with Jesus. That is far stronger than symbolic arithmetic about the extra fifth.
Where this fits in the story: Builds on the sanctuary's holiness and property consecrated to YHWH; misuse creates both ritual liability and a reparative obligation.
Where Scripture takes it next: Leviticus 22:14 repeats restoration plus an added fifth for accidental consumption of a holy thing.