The Leviton Series 2000 Power meter has two different ways to pulse out to a gateway.  

Summary

Consider:

Pulses are counted both on and off.  That is why 10 is 10 Watt/hours per pulse and 1K is 1Kwatt/hour per pulse.

10 Output Wiring – 10 Wh per pulse

1K Output Wiring – 1 Kwh per pulse