Every hours record gets a value associated with it based on the hourly value for the associated job. Usually this is considered a monetary value to the organization. For example a job with an hourly value of $14.75 done for three hours by a volunteer gets a value of $44.25.
When VSys calculates the value of an hours record it first looks to the job's definition for an hourly value. If that is zero it looks to the job group; if that, too, is zero then it takes the system's default hourly value. Because the hourly value for a job (or job group or the system) may vary from year to year, VSys lets you specify what the hourly value was in the past as well as the present. In any job, job group or the Jobs panel in System preferences and feature enabling, click on Hourly values in the past.
This brings up an editor which lets you set the value for past date ranges. In this example, the value for each volunteered hour: