Almost every figure in Subdex describes the records currently loaded, not everything that exists.
If you load 100 records and see "12 subreddits," that means twelve subreddits appear among those hundred. Loading a thousand records would likely show more.
Why it is phrased this way
The archive holds an unknown fraction of what was posted, and you retrieved a fraction of that. Two unknowns sit between a count and any claim about a person's activity.
"Archive records found" is defensible. "Total posts" is not, and the difference is not pedantry — it is the difference between a statement about your data and a claim about someone's life.
Where it matters most
Subreddit shares. A community holding 40% of loaded activity may hold much less of the account's real activity, especially if you loaded recent records and their interests changed.
Date ranges. The span shown is the span you loaded. Loading newest-first and stopping early produces a recent-looking range for an old account.
Comparisons. Comparing two accounts is only meaningful if similar amounts were loaded for both.