This thread has been really helpful, thanks folks. I am really glad I made the switch from edmunds to this forum.

Here is a summary of what I have come away with:

I was confused and thought that assist pressure and brake pressure were the same thing.

Either the assist or the mechanical backup can produce brake pressure to the calipers.

ABS bleeds brake pressure from the calipers not the assist. The ABS pump cannot repressurize the assist either, as it can only restore fluid/pressure lost during the ABS process. Therefore it does act to preserve whatever level of assist you have because it keeps you from having to further depress the pedal to restore brake fluid drained off by the ABS system. Another way of describing it is that ABS is a circulatory system, it bleeds pressure from the calipers and then pumps it right back into the master cylinder, thus keeping the main brake pressure constant.

My misconception was I thought the assist pump was used to restore fluid drained by the ABS, I did not know about the electric pump that is part of all ABS systems.

Other people who have observed that the act of depressing the pedal (as opposed to holding it) is what loses assist pressure are right on.

Therefore one can use ABS with or without assist pressure. The ABS warning light does not come on during an FAS either, so it thinks it is ok too. Thus depressing and holding the brake pedal during an FAS (even to the point of activating ABS) is an efficient and safe use of pressure, unlike pumping.

Here is a choice quote from an ABS article:

"ABS can only reduce pressure, therefore brake pressure can never be more than what the brake pedal allows".

I for one am not strong enough to activate the ABS without assist (unlike psyshakennegger, whom I respect and admire but don't have his leg strength, although I reject insinuations impugning my masculinity :-) ).

So I will now happily FAS, even at freeway speeds, but be careful to keep my brake pressure up by starting the engine anytime I release (not depress) the brake pedal.

Note: In case it is not clear, yes ABS will function with or without assist pressure if I understand things correctly and your leg is strong enough. I am looking forward to lakedude trying it.