I have continued my research on MSFS drag computation thanks to excellent debug windows.
After having tested several combination of oswald, CL0, CD0 to match desired Cl vs CD curve, I came to conclusion it was impossible to fit completely targeted curve despite it should be a simple second degree polynomial function according SDK.
I decided to plot a screenshot of MSFS Cl vs CD curve available in excel and found that MSFS CL vs CD function is much closer to a 3rd degree polynomial function than a second order one.
So I fear the SDK doesn’t give the complete explanation of internal induced deag calculation.
If one Asobo dev could guve more insight it would be interesting.