User blog comment:Da1dx/Frontier Hunter ranking./@comment-24570336-20161014184024

There are 3 types of stat buffs: Normal, Self and Conversion.

They are all unique and can stack together.

Sirius's SBB apply normal stat buffs. Avant's SBB apply conversion buff from HP to Atk. Therefore, they will stack together because they're different types of stat buffs.

"Spark Vulnerability" debuffs and "Add Element" buffs are all unique, and will only be refreshed, not stacked.