Another Cover Question

[David Hawkins 250]

Let's say PCs are setting up an ambush in a 10' wide corridor. The bad things are 40 feet away and the PCs are stacked up behind each other.

If a PC in the 2nd row makes a ranged attack, that is still +4 AC to the defender for cover? Are there any rules to cover that situation, or is it always just blanked +4 AC.

Also, what if the PCs in the front row kneel. Is there a rule to handle that, or as GM is it something you can houserule and make it only +2?

[Grick]

David Hawkins 250 wrote:

If a PC in the 2nd row makes a ranged attack, that is still +4 AC to the defender for cover? Are there any rules to cover that situation, or is it always just blanked +4 AC.

All quotes from Cover.

Soft Cover: "Creatures, even your enemies, can provide you with cover against ranged attacks, giving you a +4 bonus to AC. However, such soft cover provides no bonus on Reflex saves, nor does soft cover allow you to make a Stealth check."

David Hawkins 250 wrote:

Also, what if the PCs in the front row kneel. Is there a rule to handle that, or as GM is it something you can houserule and make it only +2?

Low Obstacles and Cover: "A low obstacle (such as a wall no higher than half your height) provides cover, but only to creatures within 30 feet (6 squares) of it. The attacker can ignore the cover if he's closer to the obstacle than his target."

Partial Cover: "If a creature has cover, but more than half the creature is visible, its cover bonus is reduced to a +2 to AC and a +1 bonus on Reflex saving throws. This partial cover is subject to the GM's discretion."

[David Hawkins 250]

So I can use the low obstacle rule w/ kneeling PCs and they provide no AC bonus since the bad guys are further away. That's kind of what I thought, but just making sure.
Thanks for answer.