Customers continue to flee Dobson Communications ( DCEL), but analysts see a silver lining.The Oklahoma City rural wireless shop says preliminary third-quarter results show its monthly subscriber defection rate rose to 2.8%, with 24,100 net users canceling service. This is an acceleration of the company's churn rate and a dramatic increase in customer shrinkage. In the previous quarter, Dobson had a churn rate of 2.25%, and lost 1,100 net subscribers. But some observers note that other measurements were stronger than expected. The company's average revenue per user rose to $46.75, well above the $46 some were expecting. The company also renewed a six-year roaming agreement with Deutsche Telekom's ( DT) T-Mobile. Dobson also agreed to lease wireless spectrum from T-Mobile in Minnesota and Oklahoma, as well as buy spectrum in Kansas, Kentucky, Michigan, Missouri, Minnesota, New York, Ohio, Oklahoma, Pennsylvania, Texas and West Virginia. The deal is expected to expand Dobson's coverage area and its roaming revenue as customers using other carriers make calls on Dobson's network. Dobson shares were down 3 cents to $7.46 in light premarket trading Monday.