$125 is for upgrading "basic" iOS/Android. Pro upgrade is $750 for each. License comparison chart is here: http://unity3d.com/unity/licenses

Edit: Note that it is possible to upgrade just your Unity 4 Pro license without upgrading the individual platforms. For instance, I have Pro iPhone/Android licenses, but currently working on a PC/Mac game, so I upgraded my Unity 4 Pro license and left the platforms for a later upgrade.