With Shelly Ibach leading Select Comfort, investors probably won’t be losing any sleep. In September, the Plymouth-based company purchased BAM Labs, the developer of Sleep IQ, a system that Select Comfort co-developed in 2012, the year Ibach took over as CEO. It measures a sleeper’s movement, heart rate and breathing, and then signals when a firmness adjustment is needed in the company’s iconic mattresses. For the 12 months ending September 30, Select Comfort maintained return on investment of 29.88 percent, far better than the industry average of 6.98 percent.