I looked at your YouTube channel and changed the default from 360 to 1080 and, like you, could not see any difference. Before I upload a video to YouTube I export the video as .mp4 (h.264) with the highest settings possible (2 pass and a variable bit rate). Though this adds to the file size it helps maintain the quality of the video. Since I primarily edit in Adobe Premiere I used Adobe Media Encoder to encode the videos. Try Handbrake (http://handbrake.fr/)
or MPEG Streamclip (http://www.squared5.com/)
to export the file as an .mp4 (h.264) file and see if that helps. Both of those programs are free downloads. I have both and have used them on various occasions. I don't recommend software I haven't personally used. Unless I am mistaken the .avi files have a tendency to be quite large.