Why is my rice coming out sticky/gummy/gunky when using my Zojirushi rice cooker?

I was so pumped to upgrade my walmart rice cooker to a Zojirushi NS-LGC05XB, but so far I haven't been too impressed.

I feel like I've been following the instructions perfectly but my rice always comes out sticky, gummy, and kinda just sticks together into a ball when I plate it.

I'm using Nishiki medium grain rice (measuring using the included cup), rinse the hell out of it until the water runs clear, fill with water to the appropriate white rice line in the pot, set it to white rice, hit start, dance along to the song it sings, and then immediately fluff with the included paddle once it's done cooking.

I might experiment with slightly less water (in my head sticky = too much water, no idea if that's accurate), or maybe letting it sit a bit instead of immediately fluffing (even thought that's what the instructions say to do).

Any tips?