If by “amendment” you mean updating financial and personal information on FAFSA and Profile for a subsequent school submission, this should not be done unless a mistake has been discovered in the first go round, in which case corrections would be sent to any school that received a form with bad information.
Absent any corrections of factual information, the same data should be sent to every school. The timing of sending the forms to different schools is up to you; just make sure that all deadlines are met.