Certificate text positioning limiation

In CoursePress Pro in Settings we go to BASIC CERTIFICATE and add our name & date completed and stuff. This works. But we would like to position text at the very bottom of the certificate. You'll notice in the PDF certificate example below that coursepress does not extend its writable area all the way down to the bottom as shown by the red box. Why? How do we write our Date of Completion and Cert No. a little lower? It always spills onto a second page if we push it beyond the red box. The red box should extend to the bottom of the very certificate, not 80 pixels above the bottom.

(the red box was added by adding style="border: 1px solid red;" to line 373 of class.basic.certificate.php to prove the limitation).