Hi Dennis
I don't know of a manufacturer making sauces deliberately, as this would be costly. The reason for rework is to use up ingredients already paid for that would otherwise have to be disposed of. You take sauce A which went wrong somehow in the factory, then add it to sauce B at different percentages. If you can't smell, taste or see sauce A in sauce B then it goes ahead and into the shops.
One thing I would say about added sugar in processed food is that it is used extensively, even more than you would imagine. Firstly, we use dextrose, glusoce, maltose, maltodextrin etc and other types of sugar as "fillers". An example is with crisp flavours. All recipes equal 100%, therefore if I develop a crisp seasoning and within it are certain flavours which are particularly strong I would use a filler to reduce the strenght of them before its applied to the crisps. Its the same with sauces. If you are to be filling a 400g jar, the sauce recipe must equal 400g, therefore dextrose is used as a filler.
The other major use of dextrose and glucose in food is in a process called "agglomeration". Examples of this are in coffee granules, gravy granules, oxo cubes etc, basically anything that needs to be disolved really quickly and not form lumps. A seasoning, say for a gravy is made, and then transfered into a huge vessel where masses of dextrose are blown in and the result is a gravy granule which dissolves instantly. Here though the sugar content has to be declared, so don't all stop drinking instant coffee, just know that filtered coffee which has to go into a caffeteire (sp?) will probably be pure coffee without having gone through the agglomeration process.
I was shocked and appalled when I discovered this fact, yes its declared on pack which is good but as a nation we eat far too much of this "hidden sugar", all of which is wheat derived thus increasing wheat intolerances as well as diabetes!!
I wish I could stop this but the industry is built on these rules. I have to say my products don't contain sugar as a filler I make sure of it!!
As a rule of thumb, read the lables on all products you buy, don't buy anything that is described as "sweet" becasue there are legal requirements that say it must conform to a certain level of sweetness and eat fresh ingredients (theres no added sugar in carrots)!!
Nic.