How should dental insurance pay packet for ortho treatment?

My wife and I bought two insurances for our daughter's ortho treatment(braces) for 2008. My wife's insurance covers $500 and my insurance covers $1000 for life time payment. I terminated my insurance for 2009. The dentist bureau billed the insurance company for at least $1,500 in Sept 2008. The insurance salaried $500 for my wife's insurance and only $650 for my insurance. The insurance company said that they pro-rated my insurance for the whole procedure. Since I terminated the insurance surrounded by the middle of the procedure, I am not honored by the full payment. My question is why my wife's amount is fully compensated but not mine. Both insurances are from the same company. Mine is more expensive than my wife's. The whole procedure costs us $6000. $1,000 is simply a portion of it. $1,000 was charged by the dentist for the service provided in 2008. Why the insurance did not cover the cost which I salaried Premium for? Is this common for all dental insurance for ortho? Is in that a place to complain? Any help is highly appreciated.
Answers:
healthplans.my-age.web - here is my health insurance plan. As I remember they can provide such a service.
My dental insurance also prorates over the term of the braces. They foot $1500 though. Braces are expensive.

Related Questions:
Dental insurance and Lumineers for teeth. Is at hand ever a means of access for insurance to repay?   Which dental insurance/plan?   Who to contact for inexpensive dental work? I am 60 and my teeth are adjectives worn down. No insurance?   Can I bring back dental insurance for myself if I am a dependent?   Do you call for cheap Health and Dental Insurance?