Another thing that occurs to me is if the resolution is high. Help suggests available resolution are from 100dpi to 600dpi with 300dpi as the nominal. Dropping from 300 to 200 should decrease the file size by about 50%; if it is 600dpi then that will drop by a factor of 36:4 or a factor of 9.
There's also a mention of PDF/A format. This format is the 'archive' format and is all plain text and can be much larger that the usual compressed format for the PDF file. Unless you expect the PDF to be opened 20 years from now, skip the PDF/A format.
As to commercial vs education:
Many companies might not, but some would hire students who bring their own copy of the software with them. In a totally honest world there would be no need for licensing at all.