I've been tracking what RR knew about the bearing box. If RR say there's no link between the 1000 and 900 failures, who's going to argue? This sort of info won't be available in the public domain unless a RR employee spills the beans. And security at Derby will be VERY tight at the moment.
It would again be nice to know when the bearing box design change was made and approved by EASA (I've seen one report that EASA hasn't approved any bearing box changes!). The fact that current RR 900 prod. line engines HAVE the h/w mod (don't know about any s/w mod) says that the design decision happened a while ago. Again, we'll only hear anything about this if a RR employee leaks something or EASA says something.
I would like to think that the bearing box mod was made as a natural design/development improvement. It was believed to be X% reliable and the new one is believed to be >X% reliable. Whatever "X" is we will never know unfortunately.