Do you think the Hemish hecher knows more about all the products than the OU, the Ou has many employees doing research on product as they are large and can do some. The hemish hescher is much smaller and needs to rely on others.
For example there is sugar (Or Corn Syrup) in the twizzlers, do you think the hemish hecher goes to the factory where the sweetner is made to investigates or just relies on the hecsher on the sweetner already (which is liklely the OU anyway)