Secondly, for APP to work this way you need to first set your frames to allow overmatter (tfover 1). Once you do this then text will print below the frame bottom as overmatter. You can then write your own scripts or code to check for overmatter and report problems. This is achieved using the getvars 21660, 21661, 21662, 21665, 21667.
If you need help with APP/3B2 scripts or configuration then there are a number of PTC partner companies who can assist. Our company GPSL (www.gpsl.co) is one of those.