In a large skillet, brown up ground beef, ground sausage, green pepper, and onion. Drain excess grease.
Stir in pasta sauce, seasonings listed under "Meat Sauce" Ingredients, sugar, and butter. Set aside.
In a large bowl mix together all ingredients listed for "3 Cheese Blend". Place cheese mixture into a large ziploc or plastic storage bag. Remove air and seal bag. Snip the bottom corner of bag.
Squeeze mixture into a uncooked manicotti tube shaped pasta halfway. Turn pasta around and squeeze mixture into other side halfway. Place filled manicotti on plate and fill rest of tubes.
Spray a 6 quart crockpot with non-stick cooking spray. Place 1/3 of the meat sauce mixture into bottom of crockpot. Layer filled manicotti on top of meat mixture. Place another 1/3 of the meat mixture on top of manicotti. Layer rest of manicotti on top of meat mixture and cover with rest of meat mixture.
Place lid on crockpot and cook on high for 2 – 2 1/2 hours until manicotti is fork tender. Sprinkle 4 oz of mozzarella cheese across the manicotti. Place lid back on and cook until cheese is melted. Sprinkle with additional Italian seasoning. Enjoy.