Question about Rating of Articles

Anyone else notice… I read an article not yet rated. It was ok, lite on detail, and completely mis-titled. I reloaded it to check the rating. I rated it a 1 and submitted it. Clicked reload page and its now a 3 of 5. So I read and rated another unrated article. I reloaded it and then rated it a 3. I immediately reloaded and it instantly became a 4.5 of 5. I might consider that ratings accumulate and are updated at certain intervals. However, why would the new ratings be instantly available immediately after I rate them? Evidence seems more than coincidental that ratings are bumped up and not to be trusted. Try it for yourself.