Mike and Martin
I tried scanning B&W negatives as if I was scanning B&W slide (i.e. the scanned image looks like the negative).
One thin I notice straight away is the improvement in hightlight areas. When I scanned B&W negs as negs, the details in bright areas are burnt. Having it scanned as B&W slides (then invert in PS later) preserve the details. Contrast is more managable.
Check this example. The hot area just above the tram has details here. Compared to the same photo but scanned as negs, that area has no details. I did try playing with curves in the scanning software when doing the earlier scan but no details can be salvaged.
The earlier scan is here:
Conclusion: indeed it's better to scan the negs as if it's a B&W slides.
PS: My scanner is the cheap 5000F flatbed. If yours is the better film dedicated scanner, then this conclusion may not apply.
Also my scanning software is ScanGear CS, very limited and pain in the @$$ to use but I have to live with it since there's no 3rd party available that I know compatible with the 5000F.