We use Official WinOLS for our tuning files, and we will show you the diferenece of our method and other tuners method. It is called extrapolation. This means use maths to get numbers. Here you will see difference.
Here you can see one opening time map, ecu siemens PPD. -in this picture you see how we changed axis, and only last row.
In the second picture you see map in 3D, As you can see, it follows a perfect proportionally like stock map designed by a Siemens Engineer.
And here other tuner map, some rows moded by percent, and axis stock, so real amount of fuel is not true. This is translated to car in incorrect consumption, timing not adjusted, because ecu thinks that fuel injected is for example 70mg and real injected fuel is 70+8%,
Here detail of percents added.
And here a 3D view of map where you can see that it isn’t proportional. Not follow the engineer design so far.