The Allegro™ XRS 20 bioreactor system is a single-use bioreactor technology designed for applications ranging from general life sciences research to seed train operations, and as a final stage reactor for small scale commercial production. In practice, many installed systems have been implemented into seed train and small scale GMP production operations, where operational simplicity and consistent results are key benefits for industrial users. In the application note summarized here, we report efforts to enhance the capabilities of the existing single-use biocontainer assembly, validating cell culture performance at the extremes of the operational design, and in at least one case expanding that operational space beyond its initial design parameters. In particular, we look at the impact on seed train operations, expanding a culture from a minimal working volume of 2 liters to final 6.25 liter volume, maintaining a tight control of mixing, mass transfer and temperature parameters over this volume range. We also successfully extended the maximum working volume by 25%, from 20 liters to 25 liters; providing cell culture performance data at both volumes that indicate equivalent performance and identical product quality characteristics in an industrially relevant CHO cell line cultivated in a fed batch process. Finally, we demonstrated excellent temperature control and good biocontainer integrity at the operating volume extremes.