I'm also not a native speaker, so writing long stuff takes some effort D:

Oh well, what I wanted emphasize on is that the answer to your question is not that easy. There is no rule that everything that is 95% off gets bundled - although almost everything that is that low has landed on it.
However that doesn't mean that games with e.g. 90% off won't land on the bundle list.

Since no one can give you a completely satisfying answer I wanted to encourage you to look further into this. You could search for terms like "contributor value", "region pricing", "level drop" or something like that, which includes all the themes around this bundling stuff.

You should always keep in mind that support just wants to create a more or less "fair" value system and that means that there can be exceptions to these bundling rules and that one should be aware of that - or he/she will be disappointed when they didn't understand something about it correctly.