As noted above, the county farm was a fixed sum, established in the twelfth century and unchanging thereafter. County revenues, and the government's need for cash, on the other hand, were not static, particularly in a period of rising prices. The Exchequer had to deal with a growing gap between fixed farms and the potential revenues of the counties. Farmer sheriffs could reap excess personal income if they had only to pay an amount set when prices were much lower. The Exchequer recouped at least some of this excess, not by increasing the farm, but by imposing additional obligations on sheriffs.
In a few counties (Bedfordshire and Buckinghamshire, Norfolk and Suffolk, Warwickshire and Leicestershire, Worcestershire) there were additional payments known as increments, over and above the farm. These too became fixed and were simply repeated year after year in the pipe rolls, usually immediately after the section concerning the farm. There were also additional sums labelled as profit, which could vary. When a sheriff was appointed, he agreed to pay the traditional farm (and increment, in the relevant counties), plus a profit. The agreed amount of profit was often recorded as part of the notification of a sheriff's appointment, sent to the Exchequer in the originalia roll. Like the increment, the profit due and the payment made (often in the form of local expenditure by the sheriff) appeared below the farm in each county's pipe roll account. Over the course of the thirteenth century, this profit figure tended to rise, reflecting both inflation and the Exchequer's continuing attempts to squeeze more revenues out of the counties. This rise in profit was only halted by the reform movement of the late 1250s, which established somewhat lower levels of profit in response to local discontent.