Hi,
if you used a Li-Ion Polymer battery, the nominal is probably 3.7V ; I think you just need to use the value in the line "nominal voltage" on the datasheet. And after a full charge the battery voltage is close to 4.2V.
for the chemistry test, I think it's better to use the datasheet value. And in my case, I consider that the battery will be dead after the test. And for the chemistry test, remenber to disconnect the protection chip on the battery pack.