PSA: Tuning the Material Rate % for EITHER Extruder will affect both!!

[1337Slewis 2]

For those who don't know to what I'm referring;

>Tune (wheel option during prints)

>Extruder 2

>Flow Rate %

>Changing this figure will also affect the flow rate of Extruder 1 by the same amount.

>Setting this figure to 115% made both extruders increase their flow.

Why is there individual settings for both extruders, whilst the figures are linked?

Why are their rates linked at all? It is made of 2 separate filament feeders.

Can anyone explain this to me?

I lost a high quality print to this madness, and would appreciate any help.