Hmmmm, no.

I get about 225 down in my house on the 5ghz network. In my garage (separate from my house) I only get the 2.4 network from my nighthawk. The nighthawk extender I have pushes the 5ghz network across my whole property and I get about 180mbps down

Can't blame him, he is team instinct.

I've seen that to be the exception rather than the rule. Is it an actual extender, or a powerline AP?

It's the respective extender for the ac1900 model. So yes, moreover an accesspoint.

AC1900 is a speed class, not a model number. That being said, the R7300 is an AC1900 class router that comes with a powerline AP (they call it a DST - dead spot terminator). The function of an AP is different than an actual wireless extender (and they tend to behave better, as well). Netgear also has the R7000 (also AC1900 class) which does not come with any other accessory components.

Saw something too cheap to pass up last month and I use it with my Nighthawk R7000. If you check coaxifi.com, there are some WiFi over coax kits that start at $4. I had the R7000 in my basement anyway so it was easy to set up. You unscrew the antennas from the router and connect the kit's adapters to the house's coaxial cabling, and the kit's antennas fit on any cable outlet. Now the RSSI is -25 dBm in a room that's 75-80 ft. from the router. I mean, $4 versus $200-$500 for mesh extenders, and it's on the same SSID.