-First, just use field points until this is figured out that will remove any error due to broadhead variances.
-Then check the 4 screws that hold the scope mount to the rail, if you did not locTite them remove them and do that, make sure they are tight! I put those in so tight I bend my Allan key.
-scope rings should be snug just like any other scope.
-Put your hands on the scope make sure each end if secure, I recently had a scope where the whole back end was loose.
-all that done we can rule out that anything is moving around.

-Rope cocker is important, but it will only affect windage, it will not be responsible for any significant vertical issues.
-using different arrows can cause slight variations but not the ones you are describing, try to use a target with multiple shooting points. Are your groups consistent or erratic?
If they are consistent then it's adjustment time, if they are erratic then something is loose on the bow or in the scope. Loose internals on scopes are not common at all.

So, consistency, are the arrows consistently off or all over the place? If it a problem with something loose in the mountings a way to check is to take the bow to a firm surface and put pressure with the palm of your hand down on the front of the scope, pushing it to the rail. Do it for a couple arrows. It will help determine if the scope is being subjected to the massive forward recoil and moving in it's mounts. You can do the same thing by putting upward pressure on the scope in the same place.
Another trick with that scope is to take off the windage/elevation caps, locate where they are sitting now and crank them both 20 or so turns in both directions, then back to where they were, and tap the scope gently with the butt end of the screwdriver before shooting.

Once you tear it all down tonight and re assemble it I think you will find it to be fine, just make sure those mount screws (the ones holding the mount to the rail) are good and tight, and Loc-Tite is used. Once all that is done the only thing left is the scope being defective, but I would be surprised if it were.

In the right hands that bow is very capable of 2" groups at 50 yards with field points.