"if only the world was perfect". A distinct advantage in avoiding such mistakes, is providing the CO with "Crew Communication devices (if available). Without ACTUAL NOWLEDGE of why the R has not signaled to restart the clock, waiting for such a signal confirmation seems "prudent". Any number of "situations" may develop delaying that signal; a nearby injured player, a (rational) question/objection by nearby coach, a delayed dissenting question by a fellow Official (spot, unseen flag, etc.). The Clock is STOPPED (and so is time), whereas improperly re-starting the clock without an appropriate signal will likely require a subsequent timing correctio.
If delaying starting the clock was appropriate, no adjustment (further explanation) is necessary. If adjustment is necessary, simply resetting the clock (under direction of the R, is available. Stopping/restarting the Game Clock is a decision DIRECTED by FIELD Officials to a CO, which at times may be subject to adjustment by Field Officials. The availability of including the CO in constant communication capabilities is a distinct asset in avoiding/minimizing problems.