Memory utilization doesn't match memory used?

I've created an alert to trigger when Memory Utilization within a VM goes over 70%.  There are two (relevant) lines in the email:

${N=SwisEntity;M=Node.Stats.PercentMemoryUsed} memory used of ${N=SwisEntity;M=Node.Stats.TotalMemory}

Current memory utilization: ${MemoryUtilization}

When the alert is triggered, my email contains:

42 % memory used of 12.0 G

Current memory utilization: 71.09 %

Is "Memory Utilization" not the same as "Memory Used"?