New standing=Old standing+(10−Old standing)×Standing increase
The consequence of this math is that the higher your standings are, the less effective standings increase become and the more dramatic penalties become. For example, a standing loss of 1% turns 9.0 standing into 8.81 but an increase of 1% would bring 9.0 standing to 9.01.
The equation for resulting standing for receiving the same standing gain multiple times is
Would help if either CCP updated the formula or the formula actually worked as your math is exactly what my maths says but it doesnt show up in game like that.