I rarely worry about anything involving this sim. :)
However you have to take the systems valuations into consideration when making a trade offer, just like you would when buying a car, goods or services. You might only want to pay X amount for a player, but if the system puts a value of Y, it might not process the trade.
In any case I am talking more about the 4 quarters equal a dollar dilemma, than the exact value rated by the system or using it as the gospel. We all have a desire to acquire our assets at the least expensive cost possible - but some times trying to buy low comes across as buying at a deep discount, and that is the essence of what I am referring to. I was simply using the system values as an example.
Besides if you have seen some of the trades that go down I think it is safe to say none of us really worry about the values other to ensure trades can be processed. ;)