Strange behavior when extracting method

demo.java

//code before extracting method from part marked with <selection>:

float discount;
//some code
<selection>
discount = 0 ;
if (unitPricePerQuantity() >= 100) {
     discount = unitPricePerQuantity() * 10 / 100;
}
</selection>

//method extracted from selected code:

private float discount() {
    float discount;
    discount = 0 ;  //initialization is in new line
    if (unitPricePerQuantity() >= 100) {
            discount = unitPricePerQuantity() * 10 / 100;
    }
    return discount;
}