Yes, valuation is one part. CPIM is taking average of last 3 years price, while in case of real estate we know how the valuation zooms even month to month.
However, there are people, who will NOT sell their land irrespective of price.
Even today, at Singur while TATA is working on the project, some 35-40% people have not collected their money.
In a short, Govt/CPIM has no role to play in land acquistion. Industrialists are buying land directly from farmers/owners in rest of India WITHOUT ANY PROBLEM. But Buddha is nOT allwing that to happen. He and CPIM wants to make good money out of this.