imo, that is not necessarily so...even with an amendment...if the amendment is "substantially identical" to previous language then potentially same amount of damages..i will post some discussion of this issue, only imo, and not stating that this is the "law"..or even the most current discussion

see section under intervening rights?http://reexamcenter.com/2009/09/reexamination/

Intervening Rights

During reexamination, the patent owner is permitted to make amendments to the claims undergoing reexamination. However, a claim amendment may have a significant impact on the ability of the patent owner to obtain damages for infringement of that claim prior to the issuance of the reexamination certificate. An amendment to a claim creates two important time periods for damages considerations – (1) the period between the issue date of the original patent and the issue date of the reexamination certificate and (2) the period after the issue date of the reexamination certificate until the patent is no longer in force.

The impact on damages is dependent on the scope of the amendment made in the reexamination proceeding. An amendment to a claim may extinguish past damages if the amended claim is not “substantially identical” to an original patent claim. In that case, the patent owner can only recover damages during the second period (after the issue date of the reexamination certificate). However, amended claims that are substantially identical to an original patent claim can be enforced (and damages recovered) from the issue date of the original claims.

The effect of amended reexamination claims during the second time period (after the issuance of the reexamination certificate) is governed by the doctrine of intervening rights (See Fortel Corp. v. Phone-Mate, Inc., 825 F.2d 1577, 1580 (Fed. Cir. 1987)). Intervening rights is a defense to infringing activity occurring after issuance of the reexamination certificate (Seattle Box Co. v. Industrial Crating and Packing Inc., 756 F.2d 1574, 1579 (Fed. Cir. 1985)). Section 252 (Any proposed amended or new claim determined to be patentable and incorporated into a patent following either an ex parte or inter partes reexamination has “the same effect as that specified in section 252 of this title for reissued patents.” 35 U.S.C. §§ 307(b), 316(b)) provides for two separate and distinct intervening rights defenses – absolute intervening rights and equitable intervening rights.

Absolute intervening rights are created by the first sentence of the second paragraph of 35 U.S.C. § 252:

A reissued patent shall not abridge or affect the right of any person or that person’s successors in business who, prior to the grant of a reissue, made, purchased, offered to sell or used within the United States, or imported into the United States, anything patented by the reissued patent, to continue the use of, to offer to sell, or to sell, or to sell to others to be used, offered for sale, or sold, the specific thing so made, purchased, offered for sale, used or imported unless the making, using, offering for sale, or selling of such thing infringes a valid claim of the reissued patent which was in the original patent.

Absolute intervening rights extend only to the “specific things” actually made, purchased, offered for sale, or used before the issuance of the reexamination certificate. Other continued activity after a reexamination certificate issues is covered by equitable intervening rights defense. Absolute intervening rights apply only to tangible articles existing prior to the date of the reexamination certificate (Shockley v. Arcan, Inc., 248 F.3d 1349, 1353 (Fed. Cir. 2001)). The applicability of absolute intervening rights to a process practiced prior to the date of the reexamination certificate has not yet been addressed by the Federal Circuit.

Equitable intervening rights are created by the second sentence of the second paragraph of 35 U.S.C. § 252:

The court before which such matter is in question may provide for the continued manufacture, use, offer for sale, or sale of the thing made, purchased, offered for sale, used, or imported as specified, or for the manufacture, use, offer for sale, or sale in the United States of which substantial preparation was made before the grant of the reissue, and the court may also provide for the continued practice of any process patented by the reissue that is practiced, or for the practice of which substantial preparation was made, before the grant of the reissue, to the extent and under such terms as the court deems equitable for the protection of investments made or business commenced before the grant of the reissue.

The equitable intervening rights provision gives a court the power to allow the continued manufacture, use, offer for sale, or sale of a “thing” in situations where a defendant has made substantial preparation to make, purchase, offer for sale, or use the “thing” or in the case of process “practice of the process” (35 U.S.C. § 252).

A court may apply the equitable intervening rights provision “to the extent and under such terms as the court deems equitable for the protection of investments made or business commenced before the grant of the reissue (Id.). The statute provides no further guidance on how to make this determination. Generally, the equitable intervening rights defense protects a third party who relied to its detriment on an aspect of the original claims that was changed by reexamination.