Each co-op is on a linear timeline based on projected expected sales you set up during co-op design with your Account Executive. If sales fall below expectations, payments should come in at the expected payments put forth to your backers so the co-op stays on schedule (or, meeting expectations) for an on time completion.  

In order to keep your co-op in compliance, all invoiced sales must be paid for.  Failure to do so will result in escalation for breach of contract, as well as flagging your co-op for nonpayment of sales.