Change to 'UpdateUnitPrice' Function in Sales Line Table

In Table 37 (Sales Line), I am looking to make a change but I just want to make sure that it will not cause any adverse effects.

In Function 'UpdateUnitPrice(CalledByFieldNo : Integer)' the following code exists (I believe that it is standard Navision code):

PriceCalcMgt.FindSalesLineLineDisc(SalesHeader,Rec);
PriceCalcMgt.FindSalesLinePrice(SalesHeader,Rec,CalledByFieldNo);

I would like to change it to:

IF Quantity = 0 THEN BEGIN
  "Unit Price" := 0;
END ELSE BEGIN
  PriceCalcMgt.FindSalesLineLineDisc(SalesHeader,Rec);
  PriceCalcMgt.FindSalesLinePrice(SalesHeader,Rec,CalledByFieldNo);
END;

Essentially, I would like no price to be calculated for Sales Lines until a quantity is entered.

Any comments would be greatly appreciated.

Thank you.