are you using maya or another program? if you use maya and have maya 7.0 (like I do) then your render time should be displayed in your current render window. If not, then you SHOULD see your render time in script editor.
if that doesn't work and you still need to see render time for your frame, then you can let maya do a batch render and in render globals you should set to batch only one frame (that's not a batch render :-D).
you said it shows you batch render times, so I think this one should work.
If nothig of above works, then PM me and I will think of something. ;-)
If the worst hasn't happened yet, that's because you haven't tried everything yet!