recent trucks (like since 1996) have a pulsed signal to hold the contactors, as it takes much less current to hold then to pull in. the voltage you read may be the pulsed average.
just a suggestion, (for foothill) but starting a new thread for a new question on a differnet truck may get you a more clear answer.
I am pretty sure that ev1, which was in the original posters truck, did NOT have a pulsed signal to the contactors, and if you have a truck that old, then I would be asking about where you had the meter's leads connected.
slow contactor operation may well be because of the insulation/guides having worn groves where the moving tip rubs.