Scanning monochrome negatives on Coolscan 5000ED

After scanning slides on my Coolscan 5000 I'm starting on my B&W negatives. I scanned the slides with 16 bit depth and 4X sampling, resulting in file sizes around 115MB. The same settings on B&W result in 50 MB file sizes. Is this overkill? I've tried scanning the B&W at 8 bit depth and 1x sampling, and can't see the difference on the computer screen.

Anyone had experience with this?