Being monitored at work

I work on the tills in PC World, and I found out today that I'm now going to be monitored because of high discounts and a low strike rate for selling instant replacements (similiar to extended warranties). I find this pretty irritating seeing as the reason why my discount is so high is because a ridiculous amount of price tickets in the store are wrong and things like BOGOF offers don't get added to the system so I have to discount them manually.
As far as instant replacements are concerned, I explain the benefits to every customer but the simple fact is that most people don't want it, and the target % they set is just ridiculous. I have a pretty good strike rate for things like printers, iPods and cameras, but it asks for it on monitors and some items that are under £30, which understandably no one is ever interested in and it drags down my figures. Management complain that I should bargain and offer discounts when people say they don't want it but there is no time when I am the only person on the till and there is a queue of 10 people, and people really resent being pressured into buying things.
Now I have to find a manager every time I need to discount, which is absolutely ridiculous. What am I supposed to do when there is a long queue and they are not around (which is always)?
This post has pretty much been one long whinge, but anyway I am interested in hearing other peoples stories of being on some kind of probationary thing, especially if you work somewhere similar.

I'm a supervisor at Sainsbury's and if someone is making mistakes then we monitor them secretly over a period of about a month (for example we check the amount of money is correct in the till

I work on the tills in PC World, and I found out today that I'm now going to be monitored because of high discounts and a low strike rate for selling instant replacements (similiar to extended warranties). I find this pretty irritating seeing as the reason why my discount is so high is because a ridiculous amount of price tickets in the store are wrong and things like BOGOF offers don't get added to the system so I have to discount them manually.
As far as instant replacements are concerned, I explain the benefits to every customer but the simple fact is that most people don't want it, and the target % they set is just ridiculous. I have a pretty good strike rate for things like printers, iPods and cameras, but it asks for it on monitors and some items that are under £30, which understandably no one is ever interested in and it drags down my figures. Management complain that I should bargain and offer discounts when people say they don't want it but there is no time when I am the only person on the till and there is a queue of 10 people, and people really resent being pressured into buying things.
Now I have to find a manager every time I need to discount, which is absolutely ridiculous. What am I supposed to do when there is a long queue and they are not around (which is always)?
This post has pretty much been one long whinge, but anyway I am interested in hearing other peoples stories of being on some kind of probationary thing, especially if you work somewhere similar.