Difference between SAC on the Ocean & App <-> Reality

[trianst]

Yesterday I went diving, and after importing the dive into the Suunto app, I saw that my SAC was 8.5 l/min.
After transferring the JSON file to my preferred diving app, it showed 10.01 l/min instead.
The Ocean also displayed 8.5 l/min. I then calculated the SAC myself using the values for pressure difference, dive time, average depth, and tank size, and I also get around 10 l/min.

So now I’m wondering how the value of 8.5 l/min is calculated and why the discrepancy is so large.
Could this possibly be an error in the Ocean’s calculation?

It’s not about the air consumption itself — I would like to understand why the Ocean displays a different (lower) SAC value.

Here is the dive data: dive time 102 min, air consumption (221 -> 112 = ) 109 bar, average depth 6.1 m, tank size 15 l.

The Ocean is running the latest firmware version (2.51.28).

Thank you very much in advance for your support.