We over-provision customers by about 10% on all of our plans to ensure speeds come through. If someone has a 100Mb plan, I can load up our backend and it will actually be alotted 110Mb. I’m guessing something similar is happening in your situation.

Cable dude here. Noise resides in the really low frequency range on the spectrum, right where modem transmission signals also travel. Your modem’s signal likely travels through multiple amplifiers on the way to the central office/headend. These amplifiers can’t distinguish between “good” radio waves and “bad” radio waves, so it just amplifies and passes along everything. Guess what else goes through these amplifiers on the way to the headend? Your neighbors signals. Depending on the size of your node, that could be a few hundred other homes all sharing that same path. Props to your isp for being proactive about it. I bet their maintenance metrics were low in your area and someone got sick of looking at it haha.