There is no little man with a green eyeshade, sitting at an IRS desk comparing Forms 8594.  There is a requirement that both parties file a Form 8594.  If they happen to match, IRS can still audit them, but is more likely to assume that they are reasonable because what's favorable for one party is usually unfavorable for the other.  Here is what Code Section 1060 says:

"If in connection with an applicable asset acquisition, the transferee and transferor agree in writing as to the allocation of any consideration, or as to the fair market value of any of the assets, such agreement shall be binding on both the transferee and transferor unless the Secretary determines that such allocation (or fair market value) is not appropriate."