I'm finding myself in the same boat. Got a replacement from Arrowhead which at first glance looks like a decent quality piece. Until you try to install. Same issue: with seal in place, arm not long enough to get the paddle to engage. A side by side comparison confirmed the original is about 4mm longer. Something else I noticed. Using the new key in the old lock, you can definitely feel a difference. The key slides in like you are putting two parts together that were made for each other. In the replacement, not the case. Every pin is a fight to get the key in and the cylinder will turn with the key not fully inserted?!?!?! The quality just isn't there. I'm calling the locksmith tomorrow.

A relic barely alive. Gentlemen, we can rebuild her. We have the technology. We have the capability to build the world's next bionic legend. Better than she was before. Better, stronger, faster.