An archived score is the value at the moment of capture. Reddit scores move for days afterwards, so an archived score is a sample, not a final figure.
The 36-hour problem
Arctic Shift captures records when they are posted, then updates them later. For roughly the first 36 hours, score and comment count carry placeholder values — typically 1 or 0 — regardless of the real figure.
Including those in a median would drag it down and produce a number that looks fine.
What Subdex does
Records captured within that window are excluded from score statistics, and the number excluded is reported alongside the result. Rows affected are marked with an asterisk in the record list.
Sorting by score
The archive sorts by date only. Sorting results by score reorders the records you loaded — it does not find the highest-scoring posts overall. The interface says so when that sort is active.