Whispersync on Kindle for PC Not Updating Consistently?

I read a lot of e-books, and lately I have been doing that almost exclusively on the Kindle (s amzn) platform. I enjoy reading books on the Kindle 2, but I augment that by reading on both an iPhone 3G (s aapl) and an evaluation ThinkPad x200 Tablet PC. The beauty of the Kindle system is the Whispersync technology that lets me register all three devices with Amazon for interaction with each other. Not only does my library get pushed around to all three devices, but as I switch among them for reading sessions, my current place in the active book gets pushed too. Most of the time.

I admit I jumped from eReader (s bks) to the Kindle because Amazon always has a lot of free good books. That’s what drew me into the fantastic series I am reading now, as the first book was offered free (and still is). Seamless switching among three readers is important to making this all work. I usually read on the Kindle 2 at home, the iPhone 3G when I’m running around, and occasionally I feel like reading on the ThinkPad in slate mode. The ThinkPad’s 12-inch screen sitting in my lap provides a reading experience much like that of a hardcover book due to the big page size.

One thing that has plagued me with the three reader process is that Kindle for the PC does not always update via Whispersync properly. I open up Kindle for PC on the slate and nothing happens. The reader doesn’t notify me that it found a reading place on one of the other devices that is further than my current position on the slate. My experience is that once this syncing fails, it is not going to redo it properly, even if I close the program and rerun it.

Both the Kindle 2 and the iPhone 3G devices sync properly every time, no matter what. It is only the PC version of the Kindle reader that sometimes fails to do so. It’s not every time — in fact it syncs correctly more often than not. But it is a royal pain when it does fail, as I have no alternative but to manually find my place in the book. I am interested in hearing from other Kindle for PC users about the syncing. Does it always work for you? Do you use three different reader gadgets as I do or do you just use one or two? The presence of the third reader in the rotation may be the cause of my problem, too.