I know that some companies lie in their accountancy but I dont know if this is a norm.
The more secure way of getting a property in Spain is to buy one already completed. There is plenty of ones and some bargains are arrising because the climate of the economy going bad.
For example, today I have heard about a 4 room flat for about 180.000 euros when the normal price for the zone was about 240.000 euros.
Also there is some medium size companies that has a solid history of good business and good developments that I think will make them to survive well these days.