Yes, there is. The out-going press moisture can be determined from a mass and energy balance of the dryer section.  By knowing the paper weight, width, speed, and reel moisture and the amount of steam used for drying, the out-going press moisture can be calculated using an analytical model of the dryer section. This is much simpler than a water balance that requires accurate measurement of many water flow rates around the press section. It is also much safer than attempting to get a "grab" sample of the sheet on the front side of the press section. It is also less costly than a cross-machine moisture scanner.  And the result is more accurate than all of these alternatives. For a "tight" well-managed dryer steam system, the sheet dryness can be determined within 0.1-0.2 dryness percent.