I assume there will be changes effective July 1, as announced in March and recent repeats. The policy change does require you specify domestic shipping service and cost. However, I think the "Other" which reverts to "see decription", i.e. not specifying is what's really being elimintated. They can't eliminate Standard Flat, as it would remove the option for use of other than the select carriers, USPS and UPS.
If you aren't using the select carriers, e.g. FedEx, I'd use Flat and NAME THE CARRIER in the description. Hopefully, that's what they want for policy compliance.
JMO
Danno