As explained on topic Understanding Revenue Commitment Fields (Answer Id: 7903) users can use form customization to set a default value equal to Yes for the Rev Rec on Rev Commit. check box on sales order.
On the other hand, when a sales order is created from an estimate, the Rev Rec on Rev Commit. check box under the Accounting tab of the sales order remains unchecked even when it is set to be checked by default on the custom form. This is because the information forwarded to the sales order is coming from the estimate which does not have the Rev Rec on Rev Commit. check box.
Users can do either of the two scenarios below to have the check box automatically checked on the sales order created from estimates:
1. Create a workflow that would set the value of the Rev Rec on Rev Commit. check box as True upon entry.
2. Or, manually check the Rev Rec on Rev Commit. Box