Enzyme kinetics software module within a Cary spectrophotometer

We just tried the "Enzyme Kinetics" software module for the first time on a Cary UV/VIS spectrophotometer, which is separate from the Kinetics module. We are plotting absorbance of NADPH versus time. One of its features is that it can calculate the slope of the trace just after one adds the final component to the cuvette holding buffer and all other components. The user defines the time period, which is the linear portion, and the software provides the slope (the units of the slope are a little bit mysterious). This feature could save a good deal of time when one has multiple runs, but there are a couple of software...curiosities. The first is that the software asks for the micromolar (not the molar) absorptivity. IIUC this is 0.00622 per µM per cm. The second is that when we try to input this number, the software increases the value, to 0.01 if I am not mistaken. We tried writing the number in a type of scientific notation, but to no avail. Has anyone used this software module? If so, how does one put in the correct value of the absorptivity? If worse comes to worse, we will just do the slope calculation ourselves.

Edited June 25Jun 25 by BabcockHall