Quick credit costs 30 cents on PBS + 20 cents plus postage at the PO.

Instant credit carries a 55 cent fee atop the postage.

Is the difference between the two only 5 cents?

(PS I know the first instant credit 55 cent fee each month is waived for Gold Key holders.)

Monetarily, yes, if you are using Media Mail. From the Help Docs below, if a book is light enough to go First class, the difference would be 20 cents (not needed) plus the 5 cents difference. I haven't actually used PBS DC with First Class at the post office, so I don't have first-hand evidence if that is how it works in practice. 

How does Printed Postage differ from the PBS Delivery Confirmation feature?

• With PBS DC, the postage is NOT printed on the wrapper--you need to add the postage yourself.
• With Printed Postage, the postage IS printed on the wrapper.

• With PBS DC, you get your credit for sending a book as Quick Credit--when the DC barcode is scanned by USPS and the information is transmitted to the PBS site.
• With Printed Postage, you get your credit instantly, as soon as you mark the book mailed.

• With PBS DC, you pay 30 cents (to PBS, from your PBS Money) in addition to the postage you apply to the package.  If the book is being sent Media Mail rate, you also need to add 19 cents to the postage amount on the package, to pay the USPS electronic Delivery Confirmation fee. (Packages sent First Class do not need the 19 cents' additional postage.)
• With PBS Printed Postage, you pay 55 cents from your PBS Money (to PBS, deducted from your PBS Money)  + postage (deducted from your PBS Money) = 55 cents over postage cost

• With PBS-DC you must mail packages over 13 ounces by handing them to a postal employee.  This is a USPS National Security regulation.
• With PBS Printed Postage, you can mail packages over 13 ounces from dropboxes and your outgoing mailbox--the printed postage is trackable, so the USPS regulation does not apply.

• With both features:
  • you need to have PBS Money in your PBS Money account
  • you can track your shipment from your My Account page
  • you get Guaranteed Credit (if your book is lost in the mail or damaged and you have a good sending record, you still get credit for sending the book).
  • you still need to mark your book mailed before the deadline to prevent the transaction from cancelling.
  • Both PBS DC and PBS Printed Postage are optional features.  You do not need to use them to send a book.

Before the rate increase the PBS DC on first class packets scanned for free. After the rate increase the PO couldn't scan a first class packet with PBS DC without a 90 cent fee.

Thanks for your information. In future I will use the instant credit for first class packets. Still considering the DC only option for media mail although having to bring instructions with me to the PO and then needing to cajole the counter clerk into using them might well change my mind after a few gos.

Are you sure about the .90 on First Class, I thought it was still free?  If your PO knows how to properly scan the pre-printed barcodes with their software update.

The 90 cents request for first class scan happened before I went to the PO with PBS instructions. At that time, early February, they were asking 90 cents for every e-DC scan including first class despite it being free before the rate increase.