> adding weird surcharges for the bmcs to use features

While this is a true statement, I don't remember NTP client being on this list.

SuperMicro only wants a license for a online BIOS update, HP/HPE wants money for iKVM to a running OS[0] and some features making sense only in enterprise environments, like AD integrations and Dell's iDRAC... well I haven't used iDRAC without aN Ent. license for a decade, so I can't bet my $5 on the feature set.

Overall, most BMC implementations does have NTP client free of charge.

[0] You can have any time you need to install OS. You have a one or two minute limit in already running OS. Enough to for the troubleshooting.