Shipping API's incorrect since rate increase?

USPS Web Tools estimates vary significantly from USPS calculator

[rocknbil]

A few customers have been complaining about shipping, we presumed it was due to the recent hikes in USPS rates. But of course, we investigate every little thing, so . . . .

I've been running a few tests on the USPS Web Tools API's, and we are getting as much as 150-200% differences using the shipping API's vs. the USPS online calculators.

Example: from our site a test for a given weight, zip, and package returns a rate of almost $12. Enter the same parameters on the USPS site and it's about $7. The actual shipping was $6.15.

We've used the Web Tools API's for years and have a good history of how close it is, it seems like this cropped up with the recent price hikes. Been over the documentation, no errors in our queries. I do have an email in to USPS.

Anyone else experiencing this, or did I miss an important memo somewhere? :-P

[LifeinAsia]

Well, it's been how long since the rate increase and the self-service scale at the local Post Office has a note on it saying "Scale uses old rates- DO NOT USE!"

[sun818]

USPS system just changed and they also utilize dimensions as part of the shipping quote. Perhaps that is where the discrepancy is? USPS will now take factor in any dimension greater than 1 cubic foot (1728 inches) and charge you the greater price of the two (dimension or weight).

[rocknbil]

Thank you sun, my shipping algorythm takes into account package volume, dimensions, splits into multiple boxes, etc, because it supports UPS (we just don't use it.) Not sending measurements to USPS, we're talking about an 8 x 8 x 8 box. :-)

Not happening on all orders, just some, they are all small, under 3 lbs, small boxing.