If you don't like SmartPost, back out and go to another thread please. 
Why is there a $7 jump in the SmartPost rates when the identical box is 9lb 1oz, vs 9lb. Ran into this twice recently where the item was under 9lb, but the buyer ordered a second item before the first was shipped and when it was added to the same box the weight was over 9lb and the shipping cost jumped. Played around a bit and discovered the discontinuity at 9lb to 9lb 1oz.
Smartpost is the worst. It should be banned and any sellers using it should be banned. Fraud, ripoff, scam.... Oh. Wait. I like Smartpost.
I never noticed the jump. Always assumed the rates would increase smoothly, almost always looked at Smartpost in comparison to USPS PM and FedEx ground and just focused on the cheapest, and never looked at the table critically until you mentioned it.
2017 Rates
Zones 1-8 do take a huge jump from 9-10 pounds. No idea why. I would assume FedEx is pushing an agenda (getting people to flip over to Ground/Home Delivery at 10 pounds and up? Or might have to do with USPS end of things?
(And, also interestingly, the other zones increase more smoothly)
Even with the jump, there could still be some circumstances where the lack of dimensional weight consideration for Smartpost might still leave it less expensive than FedEx Ground for certain packages (too tired to do the math right now to see), but even that is only until January when Smartpost will start observing dimensional weight (which may signal the end of it's usefulness for some scenarios.)
Find the 2017 and 2018 Smartpost Rate Tables, Fee Schedule, DAS zip code lists, and other docs here: http://www.fedex.com/us/smartpostguide/guide.html
