The actual movement speed bonus received by wearing these items (Fajin Boots and Tatsumaki Sitagoromo with the appropriate augment) is less than advertised.
Tatsumaki Sitagoromo have +8% on their description, yet they only give a +6% movement speed bonus.
Fajin Boots have +18% on their description and only give +16%.
Not sure if this is a localization issue, since other languages have the same info on it, but it's still wrong. Other comparable items don't seem to be affected by the error. Both Trotter Boots and Hermes Sandals have an actual +12% effect, matching their description.