The ultimate frustration is when you have no real ability to fix the core problem. NTP (and its 'roided-up cousin PTP) are great, but they require a degree of control and influence over the end devices that I just don't have. No amount of pleading will get a battery vendor to implement NTP in their BMS firmware, and I don't have nearly enough stacks of cash to wave around to commission a custom firmware. So I'm pretty much stuck with the "black box cat herding" technique of interoperation.