Nettigo Air Monitor - AQI index

I am using Nettigo Air Monitor integration.
It has sensors for PM 2.5, PM10, BME280 readings. There is also one sensor for Air Quality Index (AQI). However, the value that the sensor returns are strings, not numbers, so the history is showing state changes rather than graphs. As a result, the AQI cannot be plotted on a graph or gathered as stats.

Should I report this in github as Issue or Feature request? Or is the code developed by Nettigo themselves?