In Towne v. Towne, 150 Vt. 286, 288, 552 A.2d 404, 405 (1988), the trial court found the applicable change in circumstances occurred on August 28, 1987, and defendant filed his motion to modify on September 8, 1987. However, the trial court set October 30, 1987 as the date for which retroactive modification of child support would commence. On review, the Court found: "The trial court stated no rationale and made no findings as to why it chose the October 30 date. While choosing such a date would be within the trial court's discretion, without any stated rationale or findings of fact on this issue, we are left to speculate as to the basis upon which the trial court . . . reached its decision. This we will not do." Id. at 289, 552 A.2d at 406.