Rule 306c, in relevant part, provides that "No motion for new trial ... shall be held ineffective because prematurely filed; but every such motion shall be deemed to have been filed on the date of but subsequent to the time of signing of the judgment the motion assails....." TEX. R. CIV. P. 306c. This rule does not apply to every premature new trial motion, but only to those that "assail" the later judgment. See id. We have previously held that a premature motion for new trial that has already been disposed of cannot "assail" a later modified judgment. A.G. Solar & Co. v. Nordyke, 744 S.W.2d 646, 647 (Tex.App.-Dallas 1988), disapproved of on other grounds by Fredonia State Bank v. General Am. Life Ins. Co., 881 S.W.2d 279, 282 (Tex 1994). Additionally, a new trial or other post-judgment motion has been said to "assail" a judgment--and extend the time for perfecting an appeal--when, "if granted, [it] would result in a substantive change in the judgment as entered." See Gomez v. Texas Dep't of Criminal Justice, 896 S.W.2d 176, 177 (Tex. 1995) (quoting Miller Brewing Co. v. Villarreal, 822 S.W.2d 177, 179 (Tex.App.-San Antonio 1991), rev'd on other grounds, 829 S.W.2d 770 (Tex. 1992)). Or, put another way, "a motion for new trial relating to an earlier judgment may be considered premature within the provisions of Rule 306c ... so as to apply to a corrected judgment 'when the substance of the motion is such as could properly be raised with respect to the corrected judgment.'" Dunn v. City of Tyler, 848 S.W.2d 305, 306 (Tex.App.-Eastland 1993, no writ) (quoting Miller v. Hernandez, 708 S.W.2d 25, 27 (Tex.App.--Dallas 1986, no writ) (construing former TEX. R. CIV. P. 377a)).