Hi Matt,
Are you trying to filter your hours report based on a value in the company custom form? Or are you trying to pull in values from a company custom form into the report? The way I read your post it's the latter and you won't need an EXISTS statement as these are purely for filtering.
To pull company custom data into an hours report you just need to tell Workfront the path to the data in text mode. See below example, in an hours report we need to tell Workfront to first look at the project, then the company associated with the project and then a custom field called "Client Country". So in our textmode we have to output a value field of "project:company:DE:Client Country"
displayname=
linkedname=project
namekey=view.relatedcolumn
namekeyargkey.0=project
namekeyargkey.1=company
namekeyargkey.2=DE:Client Country
querysort=project:company:DE:Client Country
textmode=true
valuefield=project:company:DE:Client Country
valueformat=HTML
Hope that helps.
Rich.