For the FWP, the trend (Fig. 10) was broken by two of the four reference accumulations with identical levels of N-limitation and P-excess (N/COD = 2, P/COD = 8 mg/g). These two exceptions were characterized by more active biomass growth but a less than the expected (average) final biomass PHA content after 24 h (41 and 44% g-PHA/g-VSS) due to an active biomass growth rate taking over polymer production rates during the accumulation. These differences in response for the replicated accumulation conditions suggested again that the physiological state of the biomass was not consistently the same at the start from one accumulation experiment to the next. However, for the overwhelming majority of the 22 accumulations that were performed, PHA productivity was improved by the presence of nutrients that permitted some level of sustained active biomass growth in combination with PHA storage metabolic activities. The outliers motivate a need to better understand the variability of physiological state in advance of an accumulation process.