Yes and its good to know the limits of Big O as you mentioned Big O tells you what an upper bound on something is but it will provide no answer as to which to which of two algorithms with the same upper bound will be faster. There is a field that deals with this and I watched some lectures by Robert Sedgewick called "Analytic Combinatorics" where he talks about a different analysis to do just that. He talks about being able to tell large institutional clients exactly how long an algorithm on a particular input will take and how important this was in the 1970s when computing power was much slower and far more expensive.