I do the calculation exactly how you do. But at the end of the month it seems that my current 2 days family is paying more if I ask them the same amount. And current family come between 8 to 10 days where the new family will be coming for 10 days. And if I ask more then what I'm charging form my 2 days family then the fee goes up and I don't think family 2 will accept which I totally understand as it would be way too expensive.

Arrrgg