They have 20 auditing stations.
If they man all the stations, 24 hours a day, 7 days a week, each station needs to audit one ballot every 30 seconds or so.
They're not moving nearly that fast. (And they're not always using all the stations.)
Will they speed up as they get better at it?
I clocked one ballot - it took them 29 seconds. One person pulls the ballot out of a box and hands it to another. The other person puts it on a lazy susan type of turntable then spins it to the first person who looks at it then types something into computer. It then spins to the next person who does the same and a third person who does the same. Then the original person puts the ballot back into a different box. Then it repeats.