ARGH! Possible insufficient postage

[chamino101]

Hi all,

I just sent off 21 LORs. Most were international, but about six were domestic. I have always been using a specific photo mailer from Walgreens, but I recently purchased some much cheaper ones off of Amazon. Apparently the Amazon ones are heavier than the Walgreens ones, because my postage to send them all out was about one ounce heavier.

I've always put 4 "Forever" stamps on the photo mailers, knowing that it was excess postage. Now it seems that it may be insufficient postage, but the 6 domestic mails are already in the post office's hands. I can't tell for sure, but it may be 5 cents short, or up to 20 cents short.

(To clarify, the photo mailers that I include in my LOR are short-postage, the actual LOR is paid exact postage.)

From usps.gov, it looks like if its short postage it may still come to me with postage due, but it may be returned to them. Damn.