We have today received this information from the Lumia 800 team regarding this discussion:
"We've seen your comments on the latest update for the Lumia 800 and wanted to take the opportunity to quickly address some points.
First of all, the primary target of the latest Lumia 800 update (1600.2483.8106.11500) was to enhance standby time as well as to bring an improvement to the issue reported by some customers in December, that their phone wasn't able to access the full battery charge capacity correctly. We can confirm that we have successfully tested that those improvements are working. Additionally, we've noted your concerns regarding audio and camera settings and are going to address those in a series of future updates, ie. these will not be included in this specific update. It is also important to understand that only the Nokia Update for Lumia 1600.2483.8106.11500 will introduce the mentioned improvements. If you want to see what update you have installed or what software version you currently have on your Lumia 800, please check Settings>System>About and then tap the box for "More information". The "Firmware revision number" shows 1600.2483.8106.11500 if you have installed the latest Nokia update for Lumia successfully. To make sure that your Lumia 800 is up to date and always gets the latest features, go to Settings > Phone Update and select "Notify me when updates are found". Then, as soon as a new update is available for your Lumia 800, your phone will automatically display a notification.
Also always use the original Nokia Fast USB Charger AC-16 or the Nokia Charging and Data Cable CA-185CD that came with your Lumia 800, as they are specifically designed to charge the Lumia 800 as efficiently as possible. Only a charger with an output of 1000mA will fully charge your Lumia 800 battery. If you have several Nokia chargers at home, just check the respective labels or plastic parts as the product name is mentioned there.
Last but not least, the Diagnostic App was designed for internal testing purposes. In general, your battery is fine as long as the full charge capacity is more than 1000mAh. For the future, if you are checking your battery life, more useful information on the Battery status can be found by focusing on Settings>System>Battery saver. It will tell you both your remaining battery life in percent as well as the estimated time remaining, plus the time since you last charged your phone (as soon as you have disconnected your phone from your charger). If you have concerns about your battery capacity, please contact Nokia Care (phone numbers and locations can be found via www.nokia.com/support)."