If yo do not wait until a steady solution is reached, then it is difficult to evaluate if the solution is correct or not. In this line, a good practice is to consider different values for the URF, to then monitor quantities of interest in order to know if divergence occurs at the same point in all cases.
The URF for the UDS is 0.75 by default. I have faced many situations where I have been forced to reduce it to 0.25 (together with time scale around 0.05-0.1), so do not worry about that.