When it comes to testing Google traffic you need to take into account the time of day your ads are running. With a few of my campaigns I have noticed one offer might convert during the day and another only at night. You should try playing around with when your ads run. The schedule feature in Google Adwords allows you to set when you want to run your ads, either by time or even days of the week. If you find that a certain offer seems to convert at a certain time then why waste clicks. The idea is to get your campaigns to match your audience. There is no point for certain types of campaigns to advertise during the day when everyone is at work. You might luck out and someone might be able to use the office computer to make a purchase, but why take a chance when perhaps all your traffic that converts might be in the prime time hours. If you can keep track of conversion and time of day from your current campaigns then it makes it easier to schedule. The scheduling of my campaigns has saved a lot of money and increased conversion.