Xperia Mini/pro :: ICS Update Available From Pc Companion But Not From Software Update?

When u search for software update in phone it says "you have the latest software and applications from sony ericsson. your phone is up to date." At present my android version is 2.3.4 and build number is 4.0.2.A.0.62. But when you download pc campanion it says "New Phone software version available (4.1.B.0.431)"After carrying out a software upgrade, note that:Android 4.0's hardware requirements are more advanced than previous software updates, so your phone's performance may be affected.Our commitment to offering you the best, means that once upgraded you will not be able to revert back to an older version of Android.To optimize your phone's performance, some applications may have been disabled and will not be visible on your screen. A new installed application called 'Performance Assistant' will help you enable these apps. Please also note that some 3rd party applications may not be compatible with Android 4.0. Please visit Google Play's marketplace to view apps that are compatible with Android 4.0 or contact the 3rd party developers directly for support.Flash support will be disabled, but this can be easily fixed by visiting Google Play's marketplace and downloading the latest available Adobe Flash player application. But when u find SI (Sales Item) released software table the software for xperia mini SI is 1248-9517 is released and available in PC Campanion where it can update for xperaia mini.

Q1] why it is not showing update available when try to update from phone? Is it not fully released/ not compatible/ any bug/error ?

Q2] If i update to Ice Cream Sandwich and if any problem occurs then can i revert back to an old version of android i.e gingerbread.?