I'm not surprised about the DPI and full screen issues -- you'd be astonished how few people know about the good, inexpensive, and highly flexible screen shot software that's out there. I have used
HyperSnap for nearly 30 years. It's regularly and reliably updated, it's inexpensive ($39.95, unlimited installs for a single user), and the support is absolutely amazing.
That being said -- obtaining use rights for screen shots is a royal NIGHTMARE for one. For >200? No way. (I should add that I've routinely used HyperSnap to include automatically cropped screen shots in excess of 2,000 for a single book. But all were the actual program I was writing about. Which comes under fair use, especially if you're writing about a Microsoft product for Microsoft Press.

)