defination: 1. to reduce in amount, to become void. 2. in law meaning to become void or put an end to.
Asbestos is asbestos and its dangerous in its particle form. Ie, to breathe it is serious. But, I would also spec. that to have it around in an interior place is dangerous also.
Asbestos removal, with space suit personnel is the expensive part of this. Mudding over or floating over the "bumpy" spots would be putting a band aid on the problem. And later if you decide to sell, a disclaimer of hazardous areas would bring up this ceiling and you would have to attack the problem then for sure. Failure to notify would be also very serious.
So, if the money is there, and you want it fixed for good, I would go for it and as you say, "abate the ceiling", or what I would say, "tear it out".
Do you have kids around?
Others will chime in on this for sure. This is a hot topic these days with everyone so concerned about every thing around them that could be hazardous. I wonder how our past generations lived with black mold around back then.