If it is "sloppy", it's possible the voids are completely filled with water, and no method of compaction would work. Is the water above optimum and do you have a curve for it?
Sorry to get in so late: 1% could be sufficient depending on the grading concept...if it's a large plane not broken up very much and the contractor has a good way to control the equipment (laser level, etc), I go down to 1% , but not below.
I almost never go over 4% in commercial shopping...
