This one "what constitutes instrument time" has been done to death here a while ago.
Lots of things in aviation aren't written down precisely. A lot of the time one could speculate that the reason is that it is completely unenforceable. Example: regs specify equipment to be CARRIED but don't specify equipment to be USED.
This is the same. Except in really obvious cases (a clear blue sky, and a DH of 200ft) nobody can tell exactly when the pilot became visual.
The way I look at it is that one does what one is happy with, being honest with oneself. After all, a dishonest pilot could write up all sorts of fictitious logbook entries, couldn't he?
Most IFR pilots don't have a problem with this stuff if they own a plane and actually go places. If they are renting, basic currency will be the problem that dwarfs all the others. Most pilots flying an N aircraft will be whole or part owners. And this is all about IFR currency; if you fly often then you will be current and hopefully safe.