Abstract: A method is provided for modifying calculation of a predefined procedure in a spread of financial data in a financial information system operative on a digital computer wherein data is manually input into a cell as a value, the value is prioritized above other values dependent thereon by setting a lock flag to indicate that the data is to be secured against change by subsequent recalculation on the cell and thereafter the data of all other cells which is not locked is recalculated on the basis of the priority values stored in cells designated as locked. In each case, the steps of inputting, locking, recalculating and storing are repeated for each manually entered data value. The value is recalculated upon unlocking a cell, thereby deprioritizing the data.