As you would suspect, the lower end of that rep range applies to heavier weights and the higher end to lighter weights. (legionathletics.com)
One method that I am fond of is to start at the lower end of the rep range, then spend several weeks building up to the top end, before adding weight. (rugbystrengthcoach.com)
Do I need to get all of my sets at the top end of the rep range like 6,6,6 or 8,8,8. (fitmole.org)