Definitely sounds like somethings wrong with the scope

I'd contact the dealer you bought it from, or BSA if the dealer won't replace it, but somebody should replace it for you since it's still under warranty.
As for the Crosman premier hollow points..... give em a try. Sometimes the tight fitting pellets fly the best. Your rifle, being so powerful will definitely benefit from using the heavier .177 pellets. Those wadcutters you're shooting are no doubt helping to create those 2 inch groups you've been shooting. Load that shooter with some quality domed pellets, like the 10.5 gr Crosman Premier Heavies and I'll bet you your accuracy shrinks considerably.
AS for the trigger replacement..... it is so easy to do it's amazing. The only little piece that might come off when you remove the stock is a small plastic roller that fits onto a small metal post on the side of the cocking arm. When you cock the rifle the roller, which sits in a groove machined into the inside of the stock, guides the cocking arm. When you remove the stock just make sure you lift it straight up out of the stock, then take a look at the side of the rifle and you will see the little cocking roller I'm talking about. I'm tellin ya, the trigger replacement is a breeze and it will literally transform your gun...
Let us know what happens with the scope....
Jeff