Generally the invoice is wide enough to reach over the total column only, as shown in Fig. 12. Therefore, a total amount written in the total column of the invoice will manifold onto the sales sheet, and in the column marked _Total_. A wide-carriage billing machine, if used, can be adjusted with tabulator stops to jump to any column desired. The total amount is then written therein a second time. The amount of the total column should always equal the total of all the columns placed to the right of the total column. This plan eliminates the old way of waiting until the end of the month, and then laboriously going over the sales book with one total column only, and picking out the various items according to the classification wanted. [Illustration: Fig. 12. Loose-Leaf Sales Sheet and Invoices with Columns for Distribution of Labor and Stock ] The work should be planned in a manner which permits of each day's work being finished each day—leaving nothing to accumulate until the end of the month, necessitating the retracing of steps to secure certain statistical information. In certain lines of business it is desirable to make two sales sheets, one of which is retained in a binder for an office record and the other is used for various purposes. It can be used as record of sales from a branch to a home office, each page being numbered in duplicate, and of a distinctive color. This is the plan used all over the world by the Standard Oil Company. As the sales sheets arrive at the home office, they are placed in their respective binders and are gradually made into a built-up book. The loss of a sheet would be instantly detected by the missing page number. A large French perfumery firm in New York pursues this plan, and sends to Paris the duplicate sales sheet on thin paper. It gives the home office a fine record of every invoice sent out to any customer by the branch office or warehouse. As several invoices can be manifolded on each page, and on both sides of the sheet, it is the most economical method of billing as far as stationery is involved. The name _condensed billing_ indicates this fact. In other instances, the duplicate sales sheet is wide enough only to allow quantity and description of goods to be manifolded thereon, prices and extensions not showing. This narrow sheet can be used for posting to the stock records without disclosing to that department the prices at which the particular goods have been sold. This form of the sales sheet is shown in Fig 13.