Repeatability of inflation levels, and the imaging metrics derived from them, is important in hyperpolarized gas MRI, particularly when attempting to measure a response from interventions. This work presents same-session repeatability of 5 different inflation levels and their accuracy in comparison to plethysmography measures. Further the effect of inflation level on percent ventilated lung volume and coefficient of variation was investigated. The most repeatable lung volumes were total lung capacity, functional residual capacity plus 1 liter and residual volume. Percent ventilated lung volume was repeatable to within a maximum of 2% error.