Teaser, I think it's not so bad when the liver can handle insulin properly. Normally, that's precisely what it must do, it's the primary site for insulin degradation. Imagine several feedback loops, not all the same length. The shortest is pancreas-to-liver for insulin. The longest is liver-to-liver for ketones. Within these loops are points of regulation, the liver, the pancreas, fat tissue, the gut, etc.
When all is well, the liver handles any insulin fluctuation for whatever reason promptly, it's the shortest loop. If all continues to be well, the liver should handle insulin promptly still for a time, i.e. an occasional bolus of carbs or lean protein for example. Cells that rely on insulin and other hormones signaling for growth and repair for example, adjust their receptors rather than calling for more or less of those hormones, i.e. they become more or less sensitive through activation of certain enzymes like lipoprotein lipase for example.
The long loop invokes the short loop to regulate ketone production. When ketones drop, less insulin is secreted, ketogenesis goes up, ketones go back up. When ketones go up, more insulin is secreted, ketogenesis goes down, ketones go back down. To be fair, insulin stimulation by ketones is very low compared to dietary carbs or protein. Long loop homeostasis is prompt because it invokes the short loop. The important thing here is that insulin level is different - most likely higher - in the short loop than it is in the long loop, because it is degraded in the liver at the end of the short loop, it's done its job.
Description of the main disruption helps to explain benefit of drinking ketones.
We eat carbs, insulin goes up, should all be handled by the liver - within the short loop - before it ends up in the long loop, causing all kinds of nasty things like growing fatter beyond what a normal meal would do. But, there's no way to produce that much glucose in such a short time, the system can't handle that, disruption, short loop is overwhelmed, insulin and glucose leak out to the long loop, we can measure it at the arm. Simultaneously, ketogenesis shuts down through that bolus of insulin from the pancreas.
At this point there's a problem of regulation of both short and long loop, strictly due to shut down of ketogenesis, because ketones are the true master molecule, not insulin, insulin is merely invoked by ketones. Cells require a specific balance of substrates, balance is disrupted, substrates are used less quickly than otherwise, glucose lingers longer than otherwise, BG goes up in the long loop. Until ketogenesis picks up again, until ketones flow in the long loop again, insulin must drop for that, glucose must drop for that, but it gets used less quickly than otherwise because of lack of ketones.
At this point, drink ketones.
Now we got ketones activating liver insulin receptors, short loop gets better, insulin drops through insulin-degrading enzyme, glucose drops in the short loop through inhibition of glycogenolysis, gets stored as glycogen, less glucose leaks out to the long loop, BG drops in the long loop, ketogenesis remains shut down for now, but there's ketones flowing so that's not a problem. Long loop gets better, cells begin to get proper balance of substrates, glucose gets used more quickly because ketones are flowing, BG drops in the long loop. Back in the short loop, insulin drops through lower stimulation by lower glucose coming back from the long loop to the pancreas, in turn insulin drops further in the long loop, less of it leaks out.
That's the benefit of drinking ketones in the context of disruption by a bolus of dietary carbs. In a short time, we're going from disrupted on the high side, to back down to normal on the comparatively low side. It's a short time because the system is already driving that way, we're just giving it what it's missing for overall normal regulation - ketones. Conversely, from a normal level, drinking ketones provides a much lesser benefit - the system is already normal, ketones are already flowing, regulation normal across the board. In effect, we're going from normal, to lower than normal, which is much harder to do - the system is fighting back to return to normal.
So, the increase in insulin from drinking ketones, from disruption-to-normal is much lower than the increase in insulin from normal-to-below-normal, because of all the other points of regulation along the short and long loops. So yeah, I'm not worried about a bit more insulin from drinking ketones either way.