They both are belong to automatic credit check The only difference is Dynamic contains a time/horizon/attach period .This time period used by the system where we specify time in months .EX: 2 months .System will use this period to take open orders, open deliveries etc. to get credit exposure. Within this attached time period not after this specified period, u have to do delivery after this horizon period say 3 months latter the delivery date so system will not calculate this date static check will carry out the open sales orders +open deliveries +open billing + open items, dynamic check= static check+ time horizon