RDS Cloudwatch Metrics : ReadIOPS and WriteIOPS

Under Amazon RDS Metrics we have two metrics :

• ReadIOPS
• WriteIOPS

My understanding is that the term "IOPS" refers to read and write operations collectively, so I'm a bit confused why there are two metrics here with the "IOPS" suffix. Are these just unfortunately named in a confusing way, or is there something more to the metric value that I'm missing ?

Background : I'm trying to reason about IOPS utilization for an RDS DB with PIOPS storage. e.g. (Read + Write)/Provisioned as a utilization percentage.