I have just put on a new string the other day and my group's were out a bit as well ,but after shooting 60 or so shot's my group's are now starting to come together .So the answer is "yes" but after this many shot's you should have her back down to smaller group's .I think 8" group's at 20yrds seem's a bit much and you should be over that ,but it depend's on what type of string your using on whether it could stretch that much after that many shot's .

nubo