Administaff Inc. (NYSE: ASF) reported a 0.3% increase in third-quarter profit, to $12.2 million from $12.1 million in the third quarter of 2006.

Third-quarter revenue at the Houston-based professional employer organization rose 13.3% to $383.4 million from $338.4 million in the same period last year. Gross margin slipped to 19.6% from 21.2%.

Administaff said revenue was boosted by a 9.7% increase in the average number of worksite employees per month and a 3.3% increase in revenue per worker. But gross profit per worksite employee decreased because of higher benefits costs, the company said.

Administaff Inc. (NYSE: ASF)

For the third quarter ended Sept. 30, 2007, compared with the same period in 2006.

Revenue: $383.4 million, +13.3%