Membership Id- We use membership Id for validation via online form and matching process and not for assignment.

Membership No- Is assigned the first time a payment is made via Payments2Us. When a new payment is received and the contact is created/updated, the membership number is assigned there ONLY if it is blank.

The "Override Target Contact Values" on the Merchant Facility must be set to Yes for the membership number to be assigned.

The Membership Number assigned is from the field "Membership No.".  Membership No is based of the field "Membership Id".  If the "Membership Id" is blank then the "Membership Next No." is used.

For accounts, the Membership No. is prefixed with "A".