If $u_{t}$ is near 0, then after multiplication by 100 it could be interpreted as percentage change of $x$ from period $t-1$ to $t$ , that is beacause we could approximate $log(x_{t}/x_{t-1})$ by $x_{t}/x_{t-1}-1$ "very near" the point $x=1$, when $x$ is far away from 0 then this approximation doesn't hold. Put functions $y=log(x)$ and $y=x-1$ on one plot.

If $u_{t}$ is near 0, then after multiplication by 100 it could be interpreted as percentage change of $x$ minus 100% from period $t-1$ to $t$ , that is beacause we could approximate $log(x_{t}/x_{t-1})$ by $x_{t}/x_{t-1}-1$ "very near" the point $x=1$, when $x$ is far away from 1 this approximation doesn't hold. Put functions $y=log(x)$ and $y=x-1$ on one plot.