Investigators have 80% power to detect a difference in plasma glucose as low as 10mg/dL between treatment groups.

Investigators have 80% power to detect a difference in plasma glucose as low as 10mg/dL between treatment groups. The investigators receive comments from another group of scientists that a 10mg/dL change is too small, they should expect to find changes of 15 mg/dL. The study investigators will have to redesign their study to be sure it is adequately powered for a difference of 15 mg/dL between those one the drug and those on placebo (true/false).  Explain your rationale