I want to compute the value of the radial oblate spheroidal wave function of the second kind. However, I found the value at small arguments (for example $0.5I$ in the following code) cannot be computed and it shows Overflow.
But I can definitely look up the table 15.19 in Zhang's text book  that the following result should be $-0.6809057$. Does anyone know why Mathematica can not correctly compute it? Thank you.
Example 1 (failed): Run
N[SpheroidalS2[0, 0, -I , 0.5I]]
N[SpheroidalS2[0, 0, -I , 0.5I],10]
The return is
Example 2 (success): Run
N[SpheroidalS2[0, 0, -I , 5I]]
The return is
According to @MassDefect's suggestion, I tried the following code
N[SpheroidalS2[0, 0, -I, I/2], 10]
It works and the result is
-0.6890905746 + 0.*10^-11 I
But if I type
N[SpheroidalS2[0, 0, -I, I/10], 10]
It still shows
According to @Bill Watts's answer, one can try different precision and maybe there is no Overflow. For example, if one run
N[SpheroidalS2[0, 0, -I, I/10], 50]
The result will be
-1.13893813158018132761330789352859720024513682988326 + 0.*10^-51 I
This is a good trick. However, it can not solve my problem in two aspects.
Firstly, I tried many precision scheme but it always return Overflow:
N[SpheroidalS2[0, 0, -I, 0], 200]
Secondly, I want a big numerical table for further computations. For example, the argument may begin with $0$ and end with $10 I$ with the step of $0.001I$. The Bill Watts's answer can not be applied because the requirement of the precision is different for different arguments.
 Zhang, S., & Jin, J. (1996). Computation of Special Functions. New York: John Wiley & Sons.