I think we are probably fairly close to agreement on this point. I see it like the gift of Faith versus the grace of Faith.
Everyone who is a Christian has the grace of Faith - i.e. they believe. But only a few have the gift of Faith which goes way beyond the usual to answered prayers, healing, etc.
Likewise we all have the grace to discern the Spirit who indwells us. But only a few have the gift of spiritual discernment, which goes way beyond the usual enabling one to be aware of the spiritual realm.
And not to go too far afield, it seems that the Scriptures often (and it must be for good reason) use the word "spirit" where classic types might use the word "nature" or modern dudes would say "attitude," or "core response." That is also something to consder about that phrase "discernment of spirits."