Bard Variant Class

[Spyderbane]

I was adding the variant class for Bards from Ebberon where they can choose a feat (Haunting Melody, Music of Growth, Music of Making, Song of the Heart, or Soothe the Beast) at levels 3, 6, 9, 12, 15, or 18 instead of the Bard feature they would have got. I created a variant class for each level. I set it up in the bonus feat section and I can add bonus feats from the list using "modified bonus fears per level" and adding the correct feats in the "additional bouns feats allowed".

I took the variant at lvl 3 and it works fine but when I take it again at another level it will not allow me to choose a new feat.

How can I set it up to allow a feat to be chosen each time you take one of the variants?