Cough medication

So I stumbled on Guaifenesin DM 100/10 labels that said the direction for kids under 12: (10 ml every 4 hours prn). Normally, it's supposed to be 5ml q4h prn. Would you change the direction and contact doctor? And is there a weight-based dose cough syrup (guaifenesin DM) for children? Many thanks.
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Source Type: forums