The technical answer to your question is that there are multiple acceptable methods for valuing a company which is why you get multiple answers. What you intend to do with the valuation will influence the method used.
In the world of finance theory there are four main formulas all of which result in slightly different results. Most valuation work will use all four methods and provide a range for the valuation. In addition to this complexity, some industries adopt a preference for one method over others when valuing companies for sale. For example, Banks tend to be valued on assets, and BPO companies tended to be valued on multiples of committed revenues. As a general rule, pay attention to articles about acquisitions in your industry. How do they report the value of the deal? If the acquisition is done by a public company, there will be reference to the price paid and a "multiple". The multiple will give you a clue regarding the relevant valuation method.
Without knowing more about your situation it is hard to give you more direction. I would be happy to discuss this off-line if you wish.
fmiltenberger@onyxassociates.com