ya mixing up your raises only applies mainly to what Sam T. illustrated.. You can also raise the same way all the time which makes it easier if people are watching you, then they couldn't ever tell what you have. Some people advocate to raise more with your Mid PP to take down the blinds, but in micro or small tourneys, people who will call a 3XBB bet will also call a 4-5XBB bet so I haven't found a good use for mixing up my bets even if my players aren't paying attention.