SEATTLE — Members of the union representing Boeing engineers overwhelmingly voted in favor of new six-year contracts, which cut some benefits while boosting others.

Importantly, the terms make it very costly for Boeing to move work done by union members outside Washington, a major concern for many members in recent years.

The agreements are with the two biggest bargaining units of the Society of Professional Engineering Employees in Aerospace (SPEEA). Members of the professional unit, which includes engineers, voted 6,085 to accept and 2,460 to reject. The members of the technical workers unit approved their contract by a vote of 2,825 in favor and 1,030 against. Votes were counted Wednesday night. The union represents 14,169 engineers and 6,024 technical workers in all.

The contracts retroactively take effect on Feb. 11 and expire Oct. 6, 2022.

​The vote had originally been scheduled to be counted on Feb. 10, but the deadline was extended due to printing and mailing errors.

“This agreement helps position us for continued success in a highly competitive landscape,” Boeing Commercial Airplanes President and CEO Ray Conner said in a statement from the company after results were announced.

​His boss, Boeing President and CEO Dennis Muilenburg, said the agreement “​recognizes and rewards the contributions of engineers and technical workers who are vital to our continued leadership in aerospace, and it will help ensure Boeing’s competitiveness in our second century of business.”

The contracts, revealed in a surprise announcement last month, came out of secret negotiations between the company and the union. Both sides committed to a streamlined, collaborative approach that set aside much of the posturing and saber-rattling that can bog down labor contract bargaining.

The contracts makes it costlier for Boeing to move work away from Washington. If that happens, the company will do everything possible to find other work for any affected SPEEA members.

Boeing promises to spend four months trying to reassign affected workers; if unsuccessful, Boeing agreed to significantly increase the involuntary layoff benefit. That payout would be a minimum of 26 weeks of pay, up to 60 weeks. Currently, 26 weeks is the ceiling for the payout.

The terms do not prevent Boeing from moving work, but doing so would be more financially painful than under the previous agreements. Boeing has moved about 4,000 engineering jobs out of the state since 2012.