@revjrblack, how is your form set up? You should only need the date range field, not the date range field and the start and end date fields because the start and end date fields are part of the date range field.
This might help you out for inserting a new record, Using the Date Range Picker with Insert and Update Record
For updating an existing record, use the same link as above, but also use this link to generate the dynamic data from the database, Using Date Range Picker with Dynamic Values