cost of nannying. please assist.

there was a post asking for cost of nannys. people said they pay $20 p/h.

what happens if families are still used to expecting $18 an hour but truly a very normal rate is 20 p/h.

also what happens if there are gaps of time. after all its not meant to be flat out cleaning job, but if the parent works from home it can be embarrassing to not be doing anything or turn on the tv or rest during a gap of time when child is asleep and all work is done.

I know someone with qualifications, and so much experience and who does so much extra to make children and families happy and supported,
families are very happy but some families still expect to pay 18 p/ h for that quality rather than 20 which even people without qualifications and all that get. but there does seem to be alot of competition for each job advertised so sometimes its better to take a bit less and have a job.
what would you do ? ask to at least do 19 p/h , wait a month till they are very happy with you and then say my rates for everyone are $20 which even people without such expertise and education recieve?

what about at night time eg 6-midnight. alot of families expect to pay $15 p/h but some of the time the child is awake and for someone with such expertise for situations that do arise, is 15 really a fair rate.

it is between the carer and the family what they are happy with.

our nanny her responsibility was soley to the children until they were sleeping. then she could do the dishes or fold some washing if she finished that well it was up to her how she spent that time until either the children woke or we got home.
She knew her role in our family as did we. we knew she was worth what we paid for her.