I am having trouble with one part of this assignment. I have everything else working but I can not get the checkDownfunction to properly check for an error. When I run the program, it always sends the alert. I assume it has something to do with this statement :

|| formData.downPayment.value > formData.stickerPrice.value)

especially the formData.stickerPrice.value portion. I thought that would work but it isn't.
I know this may not be the easiest way to do this, but the instructor wants it done this way. Here is the whole code to give you a better idea.
Code:
<script type= "text/javascript">

<!-- 
  function calcCost(formData)
  {
   
  //alert ("calcCost function reached.");
  //Input section
  var PRICE = parseFloat(formData.stickerPrice.value);
  var DOWN = parseFloat(formData.downPayment.value);
  var RATE = parseFloat(formData.interestRate.value);
  var TERM = parseInt(formData.termMonths.value,10);
  
  //calculations
  //alert (" calculating ");
  var PRIN = PRICE - DOWN; 
  var INT = PRIN * (RATE/100) * TERM / 12;
  var TCOST = PRICE + INT;
  var MPAY = (PRIN + INT) / TERM;

  //output
  //alert("Output total calcuations reached");
  formData.totalCost.value = "" + TCOST;
  formData.monthlyPayment.value = "" + MPAY;
 
  }

   function checkPrice(formData)
  {
   
  if (formData.stickerPrice.value < 0 || formData.stickerPrice.value > 100000 )
     {
     alert("Sticker price must be greater than 0 or less than $100,000");
      setTimeout (function() {formData.stickerPrice.focus();},3);
       
     }
  }

  function checkDown(formData)
  {
  if (formData.downPayment.value < 0 || formData.downPayment.value > formData.stickerPrice.value)
     {
     alert("Down Payment must be at least 0 but not greater than the sticker price."); 
     setTimeout (function() {formData.downPayment.focus();},3);
     }
  }

  function checkRate(formData)
  {
  if (formData.interestRate.value < 0 || formData.interestRate.value > 25)
     {
     alert("Interest rate must be between 0% and 25%.");
     setTimeout (function() {formData.interestRate.focus();},3);
     }
  }


  function checkTerm(formData)
  {
  if (formData.termMonths.value < 0 || formData.termMonths.value > 72)
     {
     alert("The term of the loan should be between 0 and 72 months.");
     setTimout (function() {formData.termMonths.focus();},3);

     }
  }
   
-->
 </script> 
</head>

<body>
<h1> Car Cost Calculator </h1>


<hr />


<p> This program will determine and display the overall cost of purchasing a car and the monthly payment required. 
Please enter the following data without commas, dollarsigns or percent signs by filling in the fourinput text 
boxes below. Then click on the [Calcuate] button.  The answer will appear in the two textboes at the bottom of the 
window.  To calculate with different data, click the [Reset] button and start over.</p>

<form action =''>

<h2> INPUT AREA:</h2>
 
<p>Sticker Price on the Car(in dollars):
<input type="text" name="stickerPrice" onblur = "checkPrice(this.form)" /></p>
 
<p>Down Payment(in dollars):
<input type="text" name= "downPayment" onblur = "checkDown(this.form)"/></p> 

<p>Annual InterestRate of the Loan:%
<input type="text" name ="interestRate" onblur = "checkRate(this.form)"/></p> 

<p>Term of the Loan (in Months):
<input type="text" name ="termMonths" onblur = "checkTerm(this.form)"/></p>  

<p>
<input type="button" value="Calculate" name="calcButton" onclick="calcCost (this.form)" /> 

<input type="reset" name="resetButton" value="Reset" /></p> 
 



<h2>OUTPUT AREA: </h2>
<p>The total cost for that car including interest would be $
<input type ="text" name="totalCost" /></p>

<p>The monthly payment would be $
<input type ="text" name = "monthlyPayment" /></p>

</form>

</body>
</html>
Any help would be appreciated.