Supporting interior AHU with no outside air supply.

We are working in a project pursuing LEED-CI certification, and some of the base building AHU's were short on supplying air in order to meet the demand of lay-out spaces, so the interior HVAC designer install new back up AHU´s connected to the main air supply duct of the Core&Shell system and returning the air for the interior AHU with no outdoor air. The argument of the HVAC interior designer is that the base building system already has outdoor air supply connected to return complying to ASHRAE 62.1, so according to him, the back up AHU do not need to meet the requirements of the prerequisite. I understand that all new AHU´s installed as part of the tenant scope will also need to meet the requirements, Am I Right?. Thank you for your response.