It will be the same for the first 3 days and then gets better by a whole one more day (Don't know why).
For me the counter at the 1st 3 days said it will last for 1 day and 18 hours now it says that it will last for more tan 2 days and 18 hours...
2) Wifi Tethering
Actually this will be available in Mango but as a hidden feature , Soon we will know how to enable it.
The first one is up to MS to make as nothing can be done to change any core functionality of this OS :(