There is no true way to see the difference, you have to learn how to identify it using common sense (don't mean to sound condescending....just the only way I can describe it). Meaning if you're on a condition where there isn't a large amount of volume in the midlane, and the ball you're throwing suddenly starts to 2-pin, it's probably burning up, as the heads and midlane are starting to burn up. However if you're on a shot where the oil volume is heavier, then a 2-pin can be a sign of carrydown, and the proper move is to get your feet to the right and square up your angles.
In my experience a good example of this in the past was Cheetah vs. Shark...
Shark although long had a medium volume of oil. Usually balls would start to "wiggle" a little bit towards the end of the 2nd game or so, and if you moved right most times your problems would get worse. This is because the oil was going away, and the ball was spending it's energy before the end of the pattern. The move in that case would be to go left and find "clean air" for the ball to slide through. This is why you see the pros move so far left on that pattern.
Cheetah is short but has very little taper and a higher volume of head oil. Similar to Shark where after a couple of games you would often see the ball start to wiggle, however this was usually a sign of the oil beginning to push down past the end of the pattern, so the move was to close your angles down slightly. Now you would have to move back away from the gutter shortly after that, but initially you would move right for a little time.
This isn't always true...but watching what other people's balls are doing, and what other people are throwing can help you diagnose the issue. If you're in a tournament and everyone you're following is throwing aggressive balls with surface, you'll probably have to move inside of them...if they are throwing weaker, shiny balls you might have to move further to the outside.
Hope that helps....
Little known fact: In Russian "Hope" and "Change" translate to "Tax" and "Spend"