Time to Live (TTL) operations don't affect the scaling of RU/s in autoscale. Any RUs that are consumed due to TTL aren't part of the billed RU/s of the autoscale container.
For example, for an autoscale container that has 400 RU/s to 4,000 RU/s:
Hour 1: T=0: The container has no usage (no TTL or workload requests). The billable RU/s is 400 RU/s.
Hour 1: T=1: TTL is enabled.
Hour 1: T=2: The container starts to get requests. The requests consume 1,000 RUs in 1 second. 200 RUs worth of TTL are used.
The billable RU/s is still 1,000 RU/s. Regardless of when the TTL deletes occur, they don't affect the autoscale scaling logic.