Do conjunction give clear dividing line?

Hello everyone, again.
Last time I received an answer for my previous question incredibly fast enough, I was quite happy about that. I would appreciate such help again this time.

It's about a news article again, the article from UK yahoo under the name of "house prices may fall by nearly half" and seemingly very trivial matter 'and' or 'but' in the following context.

Quote: High-flying house prices could nearly halve over the next few years, a City report has predicted. David Pannell, an analyst at investment bank Durlacher, predicted house prices will fall 30 percent from their peak, with falls "sharper but shorter than in the 1980s" and added that there was a risk prices may fallas much as 45 percent.

Question: Focusing on the part saying "sharper but shorter than in the 1980s", when compared with "sharper and shorter than in the 1980s", what seems to be the difference between? If my interpretation is acceptable latter might sound like more detrimental for people took mortgage plan during the property boom whereas the people might have to incur potential loss to lesser extent than that in 1980s" when the former is the case... or is it obvious that nobody can answer because of ambiguity of how sharp and how short? Thanks for all viewed my trivial question, let your thoughts wonder, and try to find the answer for this, in advance.

Souroin