The following commentary comes from an independent investor or market observer as part of TheStreet's guest contributor program, which is separate from the company's news coverage.NEW YORK ( Trefis) -- Trina Solar ( TSL) recently disclosed in its fourth-quarter results that it posted higher-than-expected sales but a fall in gross profits. The company managed to sell 425 megawatts of panels in the last quarter compared to to its 320 to 350 megawatts in its sales guidance but its gross margins for the quarter fell to 7.1% from 10.8% in the third quarter. Trina had provided gross margins guidance of 10%. The fall in gross margins indicates that prices are falling faster than the company's cost-cutting efforts. Selling and administrative costs also increased by almost 30% in 2011 over the previous year and R&D costs more than doubled over the same period, pulling down our estimates for the company's performance. Other solar companies such as First Solar ( FSLR) also reported disappointing earnings.