[en] By simulating uvby observations under various conditions, an analysis has been made of the precision reachable by a photometric reduction algorithm proposed in an earlier paper (Manfroid and Heck, 1983). The influence of variations in parameters, such as the number of nights or the number of standard stars, is discussed. It is shown how the grouping of nights in the reduction procedure allows the observer to spend less time on standard stars measurements, while improving the accuracy of the results. The difficulty of giving a realistic value for the precision of the reductions in actual conditions is stressed. The inclusion of secondary standards is also recommended.