How do people get such high numbers of items? I average about 20 on bars, 30 on coffee, 25 on infusions, 20 on truffles, and 20 on exotics. Yet I read posts where people say they get 50-70 per item. Am I doing something wrong? Or are they using some sort of cheat?

I don't know of any cheats.  I get high factory numbers but just making the chocolates over until I'm satisfied with the amount.  Being able to produce large numbers of products is especially important at the end of the game when the orders are in amounts of 100+.  It's not always affordable to have more than one factory working on an order so you need to put out as much as possible at each one.
 
Carla K

Hi, I don't know of any cheats either, it's just how accurate and fast you are with your shooting.  I average about 20-23 bars, 30-35 coffees, 40-60 infusions and about 35-45 truffles, but i can't seem to get past 30 on exotics.  I like the recyclers, but I think it slows you down sometimes.  If I'm tired, I start shooting them into anything and they get white, just to get it up 1 or 2 more to finish - oh well.  I often do multiple factories on same product too!  Hope this helps, Have fun :-))

I definitely don't think its a cheat--its just a matter of getting the timing right. If you play it a few times (addicts like me will do that) it gets really easy. I make sure I get a certain minimum number of cases for each product and it will take 1-3 tries for me to get.
40-45 for bars--the key here is to make sure to fill all the baskets up so the five of them get 'taken' at the same time.  You should be able to do this 3-4 times before the machine starts spinning too fast
50-60 for coffee--should be easy enough. Key is to find rows that are already set in two or more items so you only need to shoot one item to make them count. Sometimes I intentionally waste an ingredient to slow the belt down.
80-100 for infusions--Of course the colours make it a lot easier, but you have to also allot about half the baskets for red, half for blue. Sometimes I have a 'spare' one going in which I mix the colours, although I try to avoid this.
50-65 for truffles--same thing applies as above
30-40 for coffee blends--so hard, especially when it gets to 5 ingredients.
50-60 for exotics--harder because there are three colours, but there's  recycler so I make sure I have at least one of each colour going
 
I think the whole point is to balance the machines.. make sure you have all the colours, and for the coffee make sure you are balancing the amount of each ingredient you get. The rest is up to your reflexes!