In preparation for studying the kinetics of the hydrolysis of Estane(R) 5703, published hydrolysis data for a similar poly(butylene adipate) (herein called 63 PBA) have been modeled. Poly(ester urethanes) are known to degrade by acid-catalyzed hydrolysis of the ester links, and the data on 63 PBA show that this degradation is reversible at low relative humidities (RHs). Previous work with these data was unable to fit them with concentration-independent rate coefficients. It is shown herein that, with the water-concentration model of the preceding article and the A(AC)2 mechanism of reversible hydrolysis/esterification, the experimental kinetic data that vary across temperature, RH, and starting molecular weight can be fit with a single set of concentration-independent rate coefficients.