stackID is what excludes the effect from others of the same stackID.
Consider this: one effect with stackID, say, "Strength" is present on the character. When a second effect with stackID "Strength" is applied, the first will be removed while the second is applied.
Act part is the main value for statistic scaling, like one might imagine as its level. As such it will contribute to scaling pretty much every other value within the entry; like gold value or, as you have observed, strength.
Last edited by Ameranth; 22/09/17 01:04 AM.