Split A/B Testing is the term used for having multiple ad's on each ad group in one campaign. This technique is used to test different ad text so that you can ensure each ad displayed on Google is optimised to draw as many clicks as possible.
Due to the countless number of different target markets for sponsored links you cannot use the same ad text for all of these as it will not be appropriate. It is important to have suitable creatives for every market and product you are selling or advertising, otherwise you are unlikely to draw traffic and could attract users not interested in your products.
Another point to remember is that different users will obviously be attracted to different benefits of the same product so to ensure that you are reaching everyone you need to vary the ad text.
As a knowledgeable Pay Per Click management company we know how important this testing is and therefore know the best ways to help your campaign succeed.