Does BT/PN use sync speed to save bandwidth at peak times. I have noticed an apparent >10% variation depending on when I connect: early morning being fastest, evening slowest. Just coincidence? (Same hardware etc etc etc).
Re: sync speed
So switch on your router in the morning when you get maximum sync speed, and leave it powered on all the time, and hopefully it should hold the faster sync during the rest of the day - unless you have a noisy line !