I had the same problem with a Tasco World Classscope I bought a couple years ago. I had it professionally mounted and the gunsmith (who sold it to me) said he thought there was something wrong because it took an unusual amount of adjustment to bore sight it.

I took the rifle out and it would not even hit paper, and it was alledged to be bore sighted. So I took it back to the gun shop. He took it off and mounted an identical one in it's place. That one was and still is perfect. He said he sent that first scope back to Tasco to be checked and they ended up giving him credit for it...

I'd call the company monday morning and see what they suggest... or at least the store you bought the scope from.