POI 3" low

Sounds like you have some barrel droop. Easiest, cheapest fix is to put a shim under the scope on rear ring. Adjustable rings are another option.

Also make sure your barrel screws are tight. (Two screw on top closest to barrel).

I'm not real familiar with the Dreamtac but if it has a pellet liner you can rotate it and see what that will do to your POI. I've seen rotating them change the POI 3" one direction or another. Also make sure your scope rings don't have that pin that can unscrew and keep them from setting flush down on the receiver.

jking

Many PCPs not just break barrel spring guns have significant barrel droop. You can shim as suggested above or get a 20MOA mount or adjustable rings to overcome that problem. I originally shimmed, put washers underneath the guns scope rail, then put on a 20MOA mount then broke down and got the FX No Limit adjustable mounts for my impact.

UTG 20 MOA riser mount picatinny

https://www.amazon.com/UTG-Leapers-MT-RSX20MOA-Elevated-Picatinny/dp/B01M1KP7PD/ref=sr_1_3?dchild=1&hvadid=77996657327098&hvbmt=be&hvdev=c&hvqmt=e&keywords=20+moa+scope+mount&qid=1581823089&sr=8-3

FX No Limit 30mm adjustable rings Weaver

https://www.airgundepot.com/fx-airguns-no-limit-scope-mount-30-mm-weaver.html

FX No Limit 30mm Dovetail

Cool deal, maybe it'll show up on paper as well. If it does help you can shoot it and keep rotating until your POI is at it's maximum height. That will help with down range accuracy too.

jking

The adjustable rings have one advantage. You can optically center your scope then fire a shot in a rest, the over adjust to the pellet hole by a small amount and the view in the scope is optically the best.