Important: This article only applies to older funds with an underlying ABOR. For the latest implementation, see this article.
LUSID generates journal entry lines in response to economic activity in underlying portfolios. Journal entry lines are stored in a dedicated store.
When you close or lock a period, LUSID persists all the journal entry lines associated with that period. It is not possible to change this data unless you re-open the period.
LUSID generates valuation point data when you value a fund at a particular moment in time. Valuation points, and the data associated with them, are stored in a dedicated store.
When you finalise a valuation point, LUSID persists all the data associated with it. It is not possible to change this data unless you explicitly delete the valuation point.
In summary: You can always recreate a report based on a closed/locked period or a valuation point. The persistence mechanism is future-proof against code changes in LUSID itself.