I don't think that "collecting" vs "verifying" thing practically differs in anything (except for maybe intent that I don't really care for).

They printed four of my fingers the first time (presumably for "collecting") and the same four fingers the second time (presumably for "verifying"), so it was the same procedure, taking the same time. Taking a picture of me also took the same time in both cases (I had to position myself in the frame "just right".)

With that, it should take the same time "collecting" from X people as it would "verifying" X people, and so the ratio of "first-time" visitors is irrelevant.