Wait, did you check your owner's manual on the jack points first? The reason most folks leave it flat is that on a lot of cars the drain plug sits at the back of the pan, so raising the front actually tips the oil away from the hole and you leave more old oil in there than you'd think. Your Civic might drain fine either way, but on some cars you'd barely get a trickle. The other thing is if you jack up just the front, the car isn't level, so you can't trust the dipstick to tell you if you got the right amount back in. Next time try ramps instead of a jack and stands if you just need a few inches, way faster and safer.

Why do people trust the loudest guy in the room over actual facts? Your uncle heard one story about one bad winter years ago and now it's gospel. I see this everywhere, not just with cars. New phones, new diets, solar panels, whatever. Somebody's cousin had a bad time so the whole thing must be junk. The truth is usually boring and in the middle, and boring doesn't win arguments at Thanksgiving. Twelve percent in 15 degree weather sounds about right from what I've seen.