OTS
Every number your safety case rests on, in exactly one place.
A value lives in one file. Every analysis, every requirement link and every review reads it there — so there is nothing to reconcile and nothing to be out of date.
OTS Portal
The rated power is in four places. Which one is right?
It is in a supplier datasheet, a design spreadsheet, the fault tree someone built last year, and a paragraph in the safety report. Three of them agree. Nobody is sure which three.
Changes do not propagate
A value is revised in one document. Everything derived from it keeps the old number until somebody remembers, finds it, and edits it by hand.
Evidence is assembled at the end
Coverage and traceability get compiled by hand in the weeks before a review, from sources nobody can demonstrate agree with each other.
Review cannot see the change
A binary model or a reformatted export shows as changed in its entirety. The one number that actually moved is invisible.