SleepTracker: my data

Night 1. I went to bed at about 0:45h and took me some time to fall asleep, lets say around 1:30h am. Next morning the alarm went off at 7h and I was sleeping, thus I woke in shock. The data collected were:

Data01= 0:30h ; Data02= 0:39h ; Data03= 0:48h ; Data04= 0:56h ; Data05= 1:21h ; Data06= 2:12h ;
Data07= 3:19h ; Data08= 5:45h ; Data09= 6:06h ; Data10= 6:29h ; Data11= 6:39h ; DataA= 33´36"

The watch correctly detected I was awake between 0:30h and 0:56h as I went to bed around 0:45h. The watch checks your status every 8 minutes from the go-to-bed time, thus between Data1 and 4 there is a 9 minute timelap. There is a 8 minutes delay between measurements. The watch records the time of the next almost-amake moment, then wait for another 8 minutes, and so forth. Despite I believe it took me a bit longer to fall asleep, there is an interval of 25 minutes to Data5 that Sleeptracker says I slept. We dissagree here. Next, data6 and 7 say I have got two 60-minute cycles of sleep. The longest sleeping cycle ended about 90 minutes later (data8). The following three cycles were quite short (data9 to 11). The last cycle started at 6:39h (data11), just 1 minute before the wake-window started. I guess, Sleeptracker did not detect any almos-awake moment before the alarm turned on at 7h. Hence, I woke up suddently and tired. The average sleeping time was 33'36" (DataA). Besides, I don't remember having dreamt. The first attempt failed: I 1, Sleeptracker 0.

I have figured out some things since I'm using Sleepracker:

• Well, it isn't new to me that I have bad sleeping. Now I have empiric data :P
• I have figured out that if the last almost-awake time is within the window, then Sleepwatch has successfully woke me up. That is the time you guess you will be sleeping.
• In my case, a window of 30 minutes seems more effective than 20.
• Finally, I have understood what the to-bed time is, so from now on it is set at 1h am.
• In night 5, my Sleeptracker behaved oddly. It awoke me but the data was gone for no apparent reason. Since this event, I had 3 more nights in which Sleeptracker didn't work at all. Well, the time was the only working feature.

Here are all the measurements taken on myself so far:

Notes:

Night 2. Alarm set at 7h, window of 20 minutes. In bed at 0:05h. Awoken at 6:48h.
Night 3. Alarm set at 7h, window of 20 minutes. In bed at 1h. Awoken at 7h.
Night 4. Alarm set at 7h, window of 30 minutes. In bed at 0:18h. Awoken at 6:34h. I have accidentally reset all data before put it down.
Night 5. Alarm set at 7h, window of 30 minutes.
Night 6. Alarm set at 7h, window of 20 minutes. In bed at 24h. Awoken at 6:41h. It took me quite some time to fall asleep.
Night 7. Alarm set at 7h, window of 20 minutes. In bed at 0:23h. Awoken at 6:59h.
Night 9. Alarm set at 7h, window of 20 minutes. In bed at 23:43h. Awoken at 6:18h. The watch woke me up about 20 min before window.