The post office sells new massless stamps.

Today I went to the post office to mail my wedding invitations. A couple of days ago, my fiance took one of the invitations to the post office to get weighed so we could figure out the postage. The invitations weighed exactly 1 ounce and so the postage was 88 cents (due to being an oversized envelope).

My fiance was skeptical that the postage would be that low, so we took it to a different post office to get it weighed. This time the scale said 1.10 ounces. That would push the postage to $1.29 per envelope, quite the difference. The woman there said to leave the invitation with her and her manager would weigh it later and call us.

The manager did call us, and said 88 cents was actually correct -- they had forgotten to zero out the scale. Whew! Saves us a bunch of money. At that point I was glad we did our due diligence.

Today, when I went to actually send the invitations (with all of the postage now on the envelopes), the same woman weighed the same invitation again and it was back up to 1.10 ounces. The post office woman accused me of adding more things to the envelope, which I couldn't have because the envelope was sealed when she weighed it yesterday. Since the readout on the scale was to the hundredths-of-an-ounce, I asked if the scale was actually measuring hundredths (I never saw a reading between 1.00 and 1.10). I got some blank stares. I asked how the rounding on the scale worked. More blank stares.

I asked if it could be the stamps -- if somehow the invitation was teetering on the edge between 1.0 and 1.1. My hypothesis was that the actual invitation weighed something like 1.03 ounces, and the stamps pushed it to 1.05 and it then got rounded up. The post office lady then took two stamps and weighed them by themselves. The scale read out 0.00. "See?," she said, "couldn't have been the stamps."

Facepalm

Luckily the story has a happy ending. One of the times she weighed the invitation after zeroing out her scale for the 6th time it came out to 1.00 ounce. So she said she would "hand cancel" them -- i.e. make sure they go out.