Image Comment not found in EXIF data

Hello,
Rennamer is doing a great job of renaming my files based on the EXIF data, I have just one problem.

I have a static camera station setup in a lab using a Nikon D5300, and have set a bunch of static EXIF details using the Nikon Camera Control Pro software. This process takes 5 clicks.

However for each image I take I need to put in one new numberID (which is not incremental sadly) and occasionally more than one images will be taken of the same object . The Nikon software can record a comment in two clicks, and when the image is taken the Image comment is stored and stays with the image, being visible in normal windows explorer listing of the file in the Comments column.
My problem is I cannot find this user comments in the Exif data and therefore it is not available to me to use in my file re-naming. I am trying to make the user's process as simple as possible, and while 3 extra clicks does not sound like much, but multiplied by c.20,000 images at this particular station, it mounts up.
Very grateful to know if I can get at this comment for my renaming
Thanks