I went in specifically for cubital tunnel testing because of numbness in the ring and pinkie fingers, etc....and they tested from the neck down to the wrist. The tech administering the test told me I had both even before the neurologist came into the room. You might want to get a copy of your EMG and NCS. Could be you have both, but your doc just wanted to address one thing at a time. Upon researching, I have learned that some docs do both surgeries at the same time. My neurosurgeon suggested both at the same time so I'm going for it...the surgery scheduler lady seemed surprised he was doing both at the same time though....probably something to do with insurance not paying as much as they would doing 2 different surgeries!?
After re-reading your post, it sounds like you might have involvement with the ulnar nerve. If you weren't tested, you might want to go ahead and get tested for it....might want to try another facility to test you also.