It's not saying the same thing is different, but the fact free will is an emergent concept that only works on the level of a person. There is no reasonable definition of free will at the atomic level, it just doesn't exist. Let's say a picture is beautiful. Well atoms can't be beautiful so hence the picture can't be beautiful. Beauty is a very high level emergent concept that only exist at that level. It's completely compatible with determinism but the fact its ultimately deterministic atoms at play is irrelevant. It's similar for free will, the cocomcept doesn't reply on determinism and that it's completely independent from it. It's about a person's actions not the underlying mechanism of how a person acts.