EXPR from flash script

Hi we are trying to translate this expr from flash to expr in vvvv , but it does not work well , may be we are not using the right LOG ,

// Natural Logarithm *********************************************************************
function LN(num){
logaritmo = Math.log(num);//* Math.LOG2E;
return logaritmo;

// Formula mortage *********************************************************************
function formula(B2, B3,B4){
// B3 convert monthly to anualy
//B3 = B312;
return (LN(B3/B312)-B2B4-B2

what are we doing wrong ?

Expr2.v4p (9.6 kB)