PD's simply cannot make such predictions. The comparison made was relative to the chosen genetic base. Had some other genetic base been used, the bull's PD would have been different, as would the statement about expected production of his average daughters. Sire evaluations for production were developed to help dairy farmers identify superior bulls. MCC evaluations are calculated for volume of milk and fat and also for fat percent.
Bulls rank differently for milk and fat, but both traits are important to farm income.
PD Dollars is a method of combining these two important PD's into a single number that is useful for improving total value of product. PD Dollars uses economic weights for milk and fat that are determined from national market values of milk and fat for the previous year. The economic weights are changed each January. Its only limitation is one common to all evaluations. It is difficult to look at an evaluation and know just how a bull ranks relative to other sires available.