Also, if the drop offs are just a few readings, then maybe you can manually interpolate those using the software. Basically look at the cadences at the ticks before and after the drop off and put the average in.
Example:
121RPM
122RPM
121RPM
120RPM
0RPM
122RPM
120RPM
Will become
121RPM
122RPM
121RPM
120RPM
121RPM
122RPM
120RPM