Can Rev. Rul. 2000-27 be applied retroactively, for example to a sale

[Scott]

Can Revenue Ruling 2000-27 be applied retroactively, for example to a sale of less than 85% of assets in 1999, so that the the seller can now make a distribution from its 401k) plan to the employees affected by that sale?

The Rev. Rul. provides that "with respect to any sale of less than substantially all the assets of a trade or business . . . occurring prior to September 1, 2000, the Internal Revenue Service will not treat the plan as failing to follow its provisions merely because the employer does not treat the termination of employment from the seller and the hiring by the buyer as a “separation from service” within the meaning of section 401(k)(2)(B) and therefore does not permit distributions from the plan to the terminated employees hired by the buyer."

I interpret this as saying that beginning 9/1/00, all sales of less than 85% of assets must be treated as a separation from service. Does this also mean that for a transaction prior to 9/1/00, the seller can choose whether or not to treat it as a separation from service?