Create a 50% paid Invoice in PDF Templates.

Where in Sugar/AOS can we change the variables available to us in the PDF templates? I looked all over in the settings and no luck, also tried browsing through the base files, but not really having any luck.

$aos_line_item_groups_total_amount

For example with that I just want to add some PHP or create a new variable that basically just multiplies that by .5 for amount still owed. My business collects 50% up front and 50% due upon completion of service. Right now I am just having to write in the amount owed in the description and no one seems to really appreciate that, not to mention it is unprofessional to a degree.

Anyone have an idea of what I am missing here? I can’t just discount the products either…

Thank you,