It does not mean that the governess on a regular takes the clothes off the line or looks after the children for longer hours on a regular basis. It does mean when mustering early the governess may step in a look after the kids in the morning. It may only happen in busy seasons such as mustering, marking, shearing, crutching, etc. That is not considered regular.
The Rule: If it happens more than twice a week then if is a regular part of the job.