Here is the response from Tom at MPI (He also send a .pdf of the 6272 switch):
Charles,
Your plan sounds reasonable as long as you understand that the lights on the 5170 will never show anything other than green with a lithium battery connected.
I'm not positive what the actual voltages are that trigger the change in color, the switch is designed as a general warning of battery state, not a lab-quality measuring device.
We have switch 6272 ( http://www.maxxprod.com/mpi/mpi-4.html ) that is designed for Lipo/Life voltages. I am attaching the instruction sheet for this switch for your perusal.
tom/MPI