I undertook an in situ degradability experiment on which I ended up finding that my results had some lag phase on water solubility for 0 h samples. On analyzing my data using NEWAY computer software, the degradability constants were such amazing figures: rapid soluble fraction, a = -5.678, slowly rumen degradable fraction, b = 146.123 and rate of degradation, c = 0.000123. How can I make these figures look reasonably meaningful? When I try to manually manipulate the figures as using SAS software it reads: PROC NLIN failed to converge. What should I do?