If you disconnect too early, your arms hold the weight. At the extremities of your arms is your weakest point of the Kinetic Chain, your wrists; struggling to keep your barrel level at the point of contact.
Real World Example
If you were to hold a 30-pound stone for 20 seconds, this task is a lot easier when you keep the stone close to your body. However, if you were to carry the stone away from your body it becomes heavier and harder to hold; this is because you’re getting away from your center of gravity. The same goes for hitting, in particular, heavy bat training. The further your arms and hands are away from your center of gravity, the more you'll struggle.
Overload and Strength
Strengthen your core, "power hitting" muscles; such as your side abdominal region. Improve Strength in your smaller "power hitting" muscles. Especially your top hand forearm, critical for a level barrel shoulder muscles used for acceleration and deceleration.
Recap: Clinton Balgera to Eric Thames
"Laser Beam Heavy Bat Side Toss. This is your money drill. Being a...