New Condition has quantity error on sales order?

I have created a new condition type for courier charge

Settings:

Condition class = A  discount or surcharge

Calculation type = C quantity

But when the sales order is created, the Calculation Type C (Quantity) turns into B  (Fixed) !

As a result,  condition amount is not  multiplied with quantity

So if the condition record = $75  and quantity is 1  the value = 75

But when the quantity is increased to 2 , even then the value remains $75  and does not convert to $150 

It is so because the calculation type on the sales order is B Fixed

Why is it that in SPRO the calculation type is C -- but on sales order in becomes B Fixed ?

Please help solve the riddle

Thanks,

SM