PHP Parsing XML

i am having some problem with parsing XML.

What i am doing: I am spliting 1 XML to many and also editing few things for new one. And it works!!

Where is problem: After Parsing not all parts are same, to be more specifc in some of them are just 2 Labor Rate Details, in another there can be 5.:

So some looks like:

  <LaborRateList>
    <LaborRateDetail>
     <Role>Labor</Role>
     <Category>1</Category>
     <Rate Cur="CZK" Unit="h" MinValue="0" MaxValue="0">250.0</Rate>
    </LaborRateDetail>
    <LaborRateDetail>
     <Role>Paint</Role>
     <Category>2</Category>
     <Rate Cur="CZK" Unit="h" MinValue="0" MaxValue="0">350.0</Rate>
    </LaborRateDetail>
   </LaborRateList>

And another:

   <LaborRateList>
    <LaborRateDetail>
     <Role>Labor</Role>
     <Category>1</Category>
     <Rate Cur="CZK" Unit="h" MinValue="0" MaxValue="0">250.0</Rate>
    </LaborRateDetail>
    <LaborRateDetail>
     <Role>Labor</Role>
     <Category>1</Category>
     <Rate Cur="CZK" Unit="h" MinValue="0" MaxValue="0">250.0</Rate>
    </LaborRateDetail>
    <LaborRateDetail>
     <Role>Labor</Role>
     <Category>1</Category>
     <Rate Cur="CZK" Unit="h" MinValue="0" MaxValue="0">250.0</Rate>
    </LaborRateDetail>
    <LaborRateDetail>
     <Role>Labor</Role>
     <Category>1</Category>
     <Rate Cur="CZK" Unit="h" MinValue="0" MaxValue="0">250.0</Rate>
    </LaborRateDetail>
    <LaborRateDetail>
     <Role>Paint</Role>
     <Category>2</Category>
     <Rate Cur="CZK" Unit="h" MinValue="0" MaxValue="0">350.0</Rate>
    </LaborRateDetail>
   </LaborRateList>

i was trying to find out how to not insert anything if there is no more labor rates. What i try was check if there is anything in variabile and if not write nothing so my code looks like:

//RATE3 PART     
var_dump($value->Contract->LaborRateList->LaborRateDetail[2]->Role);
    if ($value->Contract->LaborRateList->LaborRateDetail[2]->Role == 0)
//SOME CODE HERE

But i am getting error:

Notice: Trying to get property of non-object in C:\xampp\htdocs\xampp\provisioning\index.php on line 23
NULL 
Notice: Trying to get property of non-object in C:\xampp\htdocs\xampp\provisioning\index.php on line 24

Can somebody help me to fix it?