CloudWatch Anomaly Detection - Amortized Costs

I am trying to implement a system within my AWS account to monitor my net amortized cost to detect anomalous spend patterns and alert me when they are identified. I have explored the AWS Cost Anomaly Detection service and found that it only monitors net unblended cost. However, I have reservations that create spikes in cost at the start of the month from upfront costs. To avoid detecting these spikes as a 'false positive' anomaly, I would like to instead use amortized cost to normalize these upfront costs.

In looking at other services to do this, I started exploring CloudWatch. Can the CloudWatch Anomaly Detection capability be used to specifically track the amortized spend for an account?