The funny thing is, it works out being more realistic that way.Chekov got the Order number wrong, which was probably straight up "last show of the series, nobody gives a crap" writing.
Starfleet is more than a century old at that point. An incident mere dozen years before the episode resulted in "General Order 7" being formulated? At best, it ought to have affected a footnote on GO 228. Plus, it was an incident of little lasting impact: it was resolved in full in an episode preceding "Turnabout Intruder" by a few years, story time and airtime.
Yet if we assume that all GOs can and will feature the option of sanctions up to death penalty, and that various incidents activate (and then at their resolution deactivate) these as events warrant, it makes sense for the honor of the one active death penalty to move from GO7 to GO4 (probably also going on a hiatus in between, before and afterwards). General Orders aren't affected exclusively by the exploits of the starship Enterprise, but by all sorts of Starfleet activities.
Basically, a writing mishap turns a naive concept into something that could actually be stomached given the context... Which is more or less how the best in Star Trek comes to be.
At our most charitable, we could say that Spock gives his opponents too much credit. So they can create a convincing illusion of being Jim Kirk? Surely they have worked out a way to get that down to a tee, then, and any attempt at outmaneuvering them is futile. After all, that's how Spock himself would do it. So he only makes token gestures to show that yes, he knows the opponent is a fraud, but won't stoop down to playing his or her game.I would have him say, "We discussed a minor problem at our working breakfast on Tuesday."

Whether a soldier or a diplomat, Kirk really is duty-bound to tell blatant lies every now and then. Especially regarding his status as one of those!There's no contradiction whatsoever between "Metamorphosis" and "Errand of Mercy."
Timo Saloniemi