Sharpened Finesse/Basic Damage bugged?

I have tested this on a sub-level 20 rogue and a level 30 necro. I have tested Basic Damage at ~400% vs damage vs distant enemies at ~400% (403 and 405, respectively). Using Heartseeker as Rogue, and Bone Splinters on Necro. In both situations, the damage for Basic deals significantly less damage per attack than damage vs distant. I even tried increasing the Basic damage to 500%, and it was still doing sub-par damage in both instances. Is this temper bugged, or am I not understanding what it’s supposed to be doing?