The BaseValue is always a value on the scale before
a possible scaling is applied. If the given value is not valid in the
associated scaling the minimum of the scaling is assumed,
if there is no minimum any other obvious value will be assumed.
E.g.: assume a scale from 0 to 6 with identical scaling.
Further assume this Increment to have Distance==2 and PostEquidistant==false.
Setting BaseValue=0 would lead to main tickmarks 0; 2; 4; 6;
Setting BaseValue=1,3 would lead to main tickmarks 1,3; 3,3; 5,3;
Setting BaseValue=-0,7 would also lead to main tickmarks 1,3; 3,3; 5,3;
And setting BaseValue to 2, -2, 4, -4 etc. in this example
leads to the same result as BaseValue=0.