8.2 Limiting Terrain, specifically hills

[daxelos]

Probably this has generally been discussed allready several times, I spotted a detail, that I found nothing about.

In Afrika Korps the special rules for hills are exactly like in the ruleboook, meaning that a hill hex is absolutely limiting terrain, regardless from the position of the spotter.
"Units occupying hill may not be spotted by enemy units more than 3 hexes away!

But in Battle of the Bulge it says:
"units occupying hill hexes may not be spotted by enemy units on lower level terrain more than three hexes away.

Has anyone else noticed this?
What is your opinion, should the rule from Bulge be retrofitted to older games?
Is it relevant at all, because it is clearly different from the main rulebook?