Master of the Void description says x1.5 increase but is x0.5 increase

[namedots]

Master of the Void description says x1.5 increase but is x0.5 increase

"increase" implies addition, so an increase of x1.5 is +150%. the correct word here would instead be "multiply"

The increase in both cases is 50%, with the difference that one of them is additive and the other is compounding. The change of notation from N% to xN is making it worse.

var countedStacks = (stacks > maxStacks) ? maxStacks : stacks;
var bonusMod = (1 + (0.5 * countedStacks));  // without this mastery
if (game.talents.voidMastery.purchased) bonusMod = Math.pow(1.5, countedStacks);  // with this mastery

It could instead read: "Each Void Map in the stack multiplies the Helium gain from the stack by 150% rather than adding 50%."
It could also be left out entirely, or be replaced with an example.

[jasperfirecai2]

but it is a x1.5 increase. each map in the stack will multiply it by 1.5, which is a x1.5 increase.
0.5x increase would either halve it, or be a linear scaling like 1.5x, 2.0x, 2.5x.. which his not how it works.

the wording is not the best in the game, but 'a 0.5x increase' is not an improvement.
it also does say in the first sentence, that it's compounding instead of being additive.

[namedots]

but 'a 0.5x increase' is not an improvement

that would not be my suggestion. rather, because both of them are 50% increases, both of them should say 50% increase. and then you might say but then it looks like nothing changed. and you'd be right, that number does not change, which is why it shouldn't be described in two different ways which suggests that there is a change.

an increase is how much you increase by. if you go from 10 to 11, that is not a 110% increase. it is a 10% increase. it is a 0.1x increase, 10% and 0.1x mean the same thing.