In Richmond they have a Resource Allocation System that calculates how much money is in the person's Personal Budget based on how they answer a series of questions in their assessment. My understanding is that the hourly rate of care is based on what it would cost to provide the care via an agency. So if you decide to take the money as a Direct Payment then you should get better value for money and can use some of that money to help you to manage your staff. It makes sense, as a provider will have to cover supervision, training etc within the £12 per hour they are paid and as en employer you need to think about the on-costs of employing a PA i.e. not just tax etc, but admin, supervision, training etc.
Hope that makes sense.