I've only had one of those and mine was focused on checking the ulnar nerve - that's where my symptoms were presenting the most at that time.

and I didn't have a clue about TOS yet then - just thought it was a spreading RSI problem - duh

As I take it the test would be more likely to rule in/out - if the nerve is trapped at elbow or wrist.
I recall something about C8 testing can help to show TOS as more of a possibility.