Phsysiological model

All: I am attempting to take a Physiological model presented in the literature and place it into Nonmem with the help of the authors. A point was raised related to centering parameters which I would appreciate some feedback. In the published paper, model parameters such as Cardiac output are allometrically scaled as power models: QCO=15.87*(BW)**0.75 and gut metabolism as: K_Gutmet=THETA(2)*(WT)**0.75) My question is should I use these equations as stated in the publication or should I center the estimates as e.g., QCO=15.87*(WT/WTstd)**0.75 The weights that will be investigated go from 30 kg up to 80 kg. It would also be very helpful if one can give me an explanation as to why or why not. Thanks Andre