>Data Manipulation Language. UPDATE, INSERT, DELETE and MERGE operators are usually DML operators.

Ok, reason I mentioned this is because this situation came back. The index hasn't changed, the code hasn't changed. However, once I adjusted the SQL command two weeks ago, this was extremely fast. Now, a few weeks after, we run into the same problem again. I still have the 66% lookup that is in the execution plan which I cannot get rid.