The higher rating is a "surge" amperage, what the relay can take as an initial flow as it closes. The lower rating is a "continuous" current flow, what the relay can handle as a constant load without overheating. For instance, the "pull-in" current of a 12 volt Delco starter solenoid on most applications can be 50 amps or slightly more, while the "hold-in" winding only flows about 10 amps. A starter button used to energize that solenoid must be able to carry the momentary surge current without burning contacts, even though the average flow is much less. Solenoids work the same way, initial surge against continuous current.
Jerry
