Recent case disallows evidence of damages due to failure to properly "compute" the damages in mandatory disclosures. 

CQ, Inc. v. TXU Mining Company, LP No. 07-11134,

http://www.ca5.uscourts.gov/opinions/pub/07/07-11134-CV0.wpd.pdf

Fed. R. Civ. P. 26(a)(1)(A)(iii):

(a) Required Disclosures.

(1) Initial Disclosures.

(A) In General. Except as exempted by Rule 26(a)(1)(B) or as otherwise stipulated or ordered by the court, a party must, without awaiting a discovery request, provide to the other parties:

(iii) a computation of each category of damages claimed by the disclosing party — who must also make available for inspection and copying as under Rule 34 the documents or other evidentiary material, unless privileged or protected from disclosure, on which each computation is based, including materials bearing on the nature and extent of injuries suffered;

This is similar to Texas rule for lost profits in new businesses:

Holt Atherton Industries, Inc. v. Heine, 835 S.W.2d 80 (Tex. 1992), involved the failure of Holt to pay for the repairs to the plaintiffs̓ bulldozer. Because they did not have use of the bulldozer, the plaintiffs claimed they had sustained lost profits. Although the plaintiffs testified that they lost several contracts because they did not have the bulldozer available, they were not able to specify which contracts they lost, how many they lost, or how much profit they would have had from the contracts or who would have awarded them contracts. Id. at 85. In summation, the court did not sanction any one method for determining lost profits. However, the court warned that “once a party has chosen a particular method for measuring their lost profits, they must provide a complete calculation.” Id. at 85.