It appears the star ratings for the Silver Amulets are incorrect for two of them:

Silver Amulet - 2*, 5 grim sparks (correct)
Blessed Silver Amulet - 4*, 20 grim sparks (incorrect)
Sacred Silver Amulet - 2*, 50 grim sparks (incorrect)
Saintly Silver Amulet - 5*, 100 grim sparks (correct)

I am guessing Blessed Silver Amulet is supposed to be 3* and Sacred Silver Amulet is supposed to be 4*? The displayed curse resistance bars match the star rating.