Batch Print Creates very large PDF file size

Hello, I am using the batch print function to print multiple drawings into a single PDF. However, the resulting PDF is a HUGE file size. Typically 20 times what you would expect compared to other PDF's of similar types. I have the DPI selected to the lowest possible setting '150', (please see attached image of PDF settings). My drawings include a mixture of Model views and Sheets. For example, a 100 page drawing set is creating a PDF with a file size of 200 MB. I need to determine which settings are required to reduce the file size. Any help would be greatly appreciated!