Field help (AMCPVAL1)

This field initially displays the next value that the system will assign to the related transaction or document. It may be changed to a new value of the Sequence Number as is appropriate to the situation.

Generally, incrementing the number should create no problems beyond the obvious "gap in the series" that will result. But decrementing the number should be avoided except in very well-defined technical contexts, since collisions will result between the new sequence numbers and ones that already exist in the database (e.g., two sales orders with potentially the same number).