title: aws billing for RI instance
body: <p>I was looking at my client's aws invoice and found out the EC2 instances were grouped based on ec2 family. For ex:</p>
  
  <ul>
  <li>m4.large</li>
  <li>m4.xlarge</li>
  <li>m4.2xlarge</li>
  <li>m4.4xlarge</li>
  </ul>
  
  <p>I saw an entry of a EC2 machine of type m4.4xlarge under each group. Strangely, a different cost was applied on this same machine type (m4.4xlarge). </p>
  
  <p>Under m4.large group, m4.large machine price was applied, under m4.xlarge group, m4.xlarge machine price was applied and so on.</p>
  
  <p>Why is that? I understand that my client must have reserved instances of different machine type? But shouldn't be price based on normalisation factor?</p>
  
  <p>Or does aws adjust the number of hours? For ex. under m4.large group, it multiply the m4.4xlarge machine type usage hours to 16. And under m4.xlarge group, it mutliply m4.4xlarge machjine usage hour to 8 and so on? </p>