However, suffice it to say up-slope only garners one an additional 3/4th height increase therefore if the difference in elevation would not be 1 full level greater than the range to the target there would be no LOS to it.
Thanks, this comment above just answered it for me, especially the italicized
'full level'. The later it gets on game night, the more apt I am to not see the forest for the trees, and not see the obvious right in front of me. Imagine if you will, four hexes in an LOS-line; stream hex, ground level, ground level, level 1 hill that is also up-slope. Ordinarily, that hill hex would need to be level 2 to see INTO the stream over the two open ground hexes, but I somehow thought it also being upslope provided enough height to do so.
Full level, Chris, FULL LEVEL!