Table Logic

We use DAX 2009 Product Models to assign part numbers. Within the Modeling Tree we have set up limitations with respect to size. The Modeling Tree also needs to find a viable material billet (tube) to assign a part number. Several months ago, two materials out of four began to return a 'tube error' in all cases. This is around the time the previous administrator left for another job. I am trying to determine the logic used to select a tube in order to determine the source of the recurring 'tube error'.

The code, extracted from the Modeling Tree, for selecting a tube size is pasted below. When I enter the Application Object Tree there does not appear to be any logic associated with the AWCInventTable.

Any ideas would be greatly appreciated.

//Component = (select AWCInventTable where AWCInventTable.AWC_Material == " + MAT + ").Itemid;

select firstonly AWCInventTable
order by AWCInventTable.AWC_CrossSection asc
where

(AWCInventTable.AWC_ProductItemGrp == "20ARD"|| AWCInventTable.AWC_ProductItemGrp == "20ARS") && AWCInventTable.AWC_Material == MAT && AWCInventTable.AWC_ODInch >= ODForTube && AWCInventTable.AWC_IDInch <= IDForTube;

if ( AWCInventTable)
{
    Component= AWCInventTable.AWC_Itemid;
}

else

{
    Component='071345';
    CompUoM = 'EA';
    SizeFlag = 'CANT';
    info('Tube Error');
}