Direct Fire/Assault Questions

[Bacillus98]

Hello. I am trying to understand how combat modifiers apply to direct fire and assaults in conjunction with hex modifiers such as hexsides, terrain, ips, trenches, bunkers, and pillboxes. I will break it up in two main sections to try to explain the befuddlement. I make statements in the post which are based on my interpretation of the rules. If these are incorrect, please let me know.

DIRECT FIRE
When the game calculates for direct fire, what defense modifiers are added up? One must be able to calculate the attack value in relation to direct fire calculations. ATTACK VALUE for men is # of men/10 multiplied by either hard/soft value.

Example 1: target hex has FIELD -25%, Bunker -20%+5. Is the total percentage deducted from ATTACK VALUE in this case going to be -45%? ATTACK VALUE times 45% to give you final modifier?

Example 2: target hex has FOREST -35%, TRENCH -40%. Total percentage calculated to a whopping 75% modifier to ATTACK VALUE.

Do you add the total negative percentages to come up with the final modifier?


ASSAULT
When it comes to figuring out the nuts and bolts here, it seems even more confusing than direct fire. The rulebook states "The maximum hexside modifier of all hexsides between attacking units and the defending units, is used to modify the attackers assault value." My understanding of this passage seems to relay there is NO cumulative adding of defensive modifiers such as Base Terrain, and IP/Trenches, Bunkers/Pillboxes. I am assuming this HEXSIDE MODIFIER rule is referring to only the HEXSIDE COMBAT MODIFIER section of the parameter date dialog file, which in N44 is:

Hexside Combat Modifiers:
Trail: 0% Secondary: 0% Primary: 0% Rail: 0%
Stream: 0% Gully: 0% Canal: 0% River: 0%
Ford: 0% Lt Bridge: 0% Med Bridge: 0% Hvy Bridge: 0%
Dune: -10% Embank: -20% Dike: -30% Escarp: -40%
Cliff: -50%

The rules seem to convey to me that base terrain and IP/Bunk/Pill are useless for assault defense. Why is this? Because the second portion of the rules state "If any of the attacking units consist of vehicles, then the terrain modifier of the defending hex is applied to the attackers assault value. Note: this modifier applies to motorized and mechanized infantry when they are in Travel Mode, but not when they are DEPLOYED."
So it seems to me vehicles use TERRAIN MODIFIERS and deployed infantry use HEXSIDE MODIFIER for assaults, which you can see is almost useless for the defender unless he is on a cliff, escarp, dike, or embankment.

If you guys can clear up the confusion I'd greatly appreciate it.