Bear in mind, however, that if you have Quantity Select Box active, your customers may end up with confusing quantities in their shopping cart...

... what do I mean, exactly?

Let's say you have an ADD TO CART at the top of the page, and another at the bottom of the page.

You have QUANTITY SELECT BOXES on both, probably with the default "1" showing.

If your customers scroll down to the bottom, and put "3" in the bottom box, then add to cart, the default (as yet unchanged) number in the TOP box will over-ride this and "1" will be written to the order. So, even thought they selected 3 items at the bottom box, only "1" will show in the subsequent shopping cart.

This is not a huge issue... you could add a line of text to the shopping cart alerting customers to check (and change if necessary), their order quantities.