For a proposed manual-versus-robot cost comparison, I'm tempted to count the robot's tending time separately from occasional checks, but I can see myself making the second column disappear when it gets inconvenient. How do you budget for that attention before you've measured a real job? Not claiming an unattended shift here, just trying to stop the spreadsheet promising one.
Keep the attention as an assumption with a range, then show what it does to the decision. I wouldn't give a made-up checking interval the authority of a measured average. Also separate actively helping from having to remain available; both can matter to staffing, but adding them together blindly can count the same time twice.
That last distinction was missing from my question; I'll show the staffing constraint beside the active-task estimate, otherwise the person who has to remain nearby becomes free just because they're not touching anything.