Incandescent vs Resistive limit for GE 45604

I purchased 2 of the GE Z-Wave Outdoor Modules 45604. In the manual it states the devices plugged into it must not exceed 600 watts (incandescent), 1800W (Resistive). My Christmas lights are the larger old C9 incandescent bulbs and I have them all in a single string. When I connect my Killawatt to the string it measures out at 750 watts so would that be too much to connect to this GE outdoor module, and if I did what would it do to the unit? What is the difference between incandescent limits vs resistive and why are these limits different? Thank You

Incandescent lamps draw a higher current at switch-on when the filament is cold. This peak current could damage a dimmer or solid-state switch if it exceeds it’s current rating. It would be wise to follow the manufacturer’s guidelines.

I also opened a ticket with the manufacturer and asked them the same question. They said the same thing that because I am using incandescent lights I am limited to 600W. If I were using LED?s it would use the restive rating and I would be able to connect 1800 watts worth of lights.