Contracts will contain certain variable sums to allow for modifications or unknown elements of the work. These sums are referred to as provisional or contingency sums, and are only spent on authorization of the contract administrator. The sums allow work to progress without constant approval from the client, which may cause project delays if approval takes time. ABC will work within agreed contract sums, and advise the client at an early stage if there are any difficulties of changes. ABC recognizes the constraints of clients budgets, and aims to bring in projects below approved budget values.