How much do you charge for financial planning?

We are one of the few firms who will invoice a fixed fee for planning as opposed to requiring clients to have assets to be managed.  We bill by the hour and a typical comprehensive plan will require at a minimum of 10 hours the first year and 6 hours every year moving forward.  That equates to $2500 over initial 12 months and $1500 every subsequent year.  We can al a carte some parts of a financial plan such as estate planning or investment oversight, in which we would only bill for those hours.