They do have a special meaning in gaming terms.
The 1.2x includes other buffs in the calculations, while a +20% only considers the base stat value.
A 1.2x is almost always better than a +20%.
[Advanced Energy Control]: When utilizing advanced energy, x1.15 Attack Power Bonus, x1.2 Shield Durability Factor, +30% Machinery Core Efficiency, +20% Output Efficiency.
The alien races who were still in the mortal world were in great trouble. They used to think they were superior and they looked down on all mortals since they were the descendants of Entities.