Hi,
I can't reproduce your bug in my local website, using the same plugin that I gave you in my previous post.
So, I don't have any idea. The single thing that I can propose you is to test it in your website but I would require a backend access (access with right to update the usps extension).
You can send me a private message.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.