Folks,
Re. the FMC default 240/10,000.
The US speed limit is MAX 250 below 10,000, there is no +/- 10, or any other tolerance that is applicable in many jurisdictions, this point has "sort of " been made.
The US speed limit is a statutory limit, FAA ATC have no authority to give you a waiver, but there is the authority of the PIC under the rule FAR 91.117(d).
Tootle pip!!
PS: Don't pick me up on some of the trials of greater than 250 below 10, they were approvals by the Administrator per. FAR 91.117(a), not ATC.