It's a possibly misleading expression to say "predetermined", because that can sound like saying "not random".
You could say every spin is "predetermined", because the moment you hit "spin" the result is randomly generated in a split millisecond.
As I understand it for RTG, the same applies to the features; that is to say, the moment you hit "spin" the result is randomly generated and if the result of that spin is the feature being hit - the result of that is also randomly generated, all in the same split millisecond.
For example, if the result of your initial spin is to win say 15 free-spins - the results of those free-spins are also generated all before your initial spin has commenced on your screen.
Either way, it makes absolutely no difference to your final outcome - each spin, pick feature or free-spin is still randomly generated.
KK