Speed calculation + Alchemy Research bonus

I'm trying to plan future pulls and calculate speeds for the future characters but I can't get the formula to work correctly.

For example, with Esty's 277 speed, a 11.75 memoria, 10 SPD accessory, and the 18% Accessory speed up, her speed should be 321, but her in-game speed shows up as 320. Does anyone have a correct formula?