"Total" in graph is not correct if derivative time span is lower than input interval

I’m running Grafana 6.6.0 under Ubuntu 18.04 with an Influx data source populated by Telegraf.
Today I wiped a 1TB disk by simply using dd from /dev/zero to disk.

Telegraf writes its data to the disk every 10 seconds. So creating a graph with derivative(10s) returns the amount of data written over the past 10 seconds. Which results in a data rate of ~1.4GiB per 10s.

Since it is more common to display the data in bytes/s, I changed the query to derivative(1s).
Now the amount of data written to disk changed from 931GiB to 93.1 GiB (see screenshot).
Bytes per Second-Cropped|443x500

Is there an elegant way of letting Grafana display the bytes/s and still have it calculate the Total correctly?
Changing the group-by time to 1s does not change anything…

Thanks a lot in advance.