seems like they have a budget for expenditures on claims and if they are going to exceed that budget, they just deny claims and effectively punt to pay on it later. 

In addition, they have a lot of boxes to check and if those boxes aren't checked properly, they deny the claim. Sometimes it feels like they create new hurdles for providers to go over just to add to that list of check boxes so they can deny more claims. For example, just recently dental insurance companies are requiring offices to put the exact date of prior crown placements. You can't just look at your records and say, "this patient has been coming here for 15 years and it was done prior to this office." They are asking for the specific date which requires contacting the previous dentist or insurance to find out that date. 

Just another stupid step that they can use to deny claims.