Barding doesn't benefit from lesser slayer bonuses

ForeverFun

From (link), and expanded for other details.

1) it appears the triple damage slayer for barding doesn't work.  It caps out at super slayer damage (2x) using ordinary slayer instruments.

• Lizardman target
• Discord mastery set
• Despair song.
• (may also apply to tribulation mastery song, haven't tested).
  
• 4x legendary (real skill) bard.
  
• Energy damage type selected in mastery book. (lizardman 0 energy resist)
  
• Double click specific instrument before test, to select it.
  
• Exceptional instrument ticks for 72 dmg.
• Super slayer (reptile) ticks for 144 dmg.
• Lesser slayer (lizardman) ticks for 144 dmg.

2) normal usage of barding skills

• exceptional crafted instrument nets 10% bonus to chance to bard the creature.
• super slayer instrument nets 20% bonus to chance to bard the creature.
• lesser slayer instrument should net 30% bonus to chance to bard the creature.  It appears this may be 20%.
  

Possible cause/explanation:  lesser slayers were added after the barding masteries and were not retrofitted to barding.

Expected result:  usage of lesser slayers should convey additional bonus beyond super slayer instruments.

quickblade

Pretty sad that both lesser+ super slayers do not stack, I was hoping that bards get some love and have decent damage with the despair song and these plunderplukers, lots of cool ideas and theories all gone, it would be appreciated if they could stack  like it should be, thanks.