It sounds like you are confusing TurnKey Linux (the virtual appliance library) with TurnKey Hub - the cloud deployment service.
Currently TurnKey Hub only supports deploying TurnKey Linux appliances. Maybe in the future that will change but right now that means you can't deploy an appliance based on RHEL.
That doesn't mean you can't use it to deploy your company's software, it just means you'll have to use one of the existing TurnKey appliances as the base and not some other Linux distribution.
TurnKey Hub is a cloud deployment service for TKL appliances
Currently TurnKey Hub only supports deploying TurnKey Linux appliances. Maybe in the future that will change but right now that means you can't deploy an appliance based on RHEL.
That doesn't mean you can't use it to deploy your company's software, it just means you'll have to use one of the existing TurnKey appliances as the base and not some other Linux distribution.