USPS shipping

We have a customer who has their storefront configured to use the stock USPS Shipping option. Their account is set up with the storefront and they have their available shipping methods selected, one being Media Mail Parcel. They are having a problem where some items in their test orders do qualify to be sent via Media Mail Parcel, but it is giving that shipping type as an option for the entire order, even the items that do not qualify for Media Mail Parcel. I was wondering if there is a way to specifically mark which items qualify for that particular shipping method, or is this an error within the storefront USPS connection?

Not out of the box.  It requires customization, or the Shipping Director plugin can do it:
https://www.noptools.com/blog/27/exclude-shipping-options-from-carrier-plugins

I do have the same issue with USPS plugin. Can somebody address the issue please

enleini23 wrote:
As per above, "It requires customization, or the Shipping Director plugin can do it"