I have no idea of the reasoning behind the issue date becoming the application date.
However;
It does occur to me though, that were they wishing to set themselves up for a repeat of the recent pressurised scenario with everybody yelling at them, they would give everybody who applied before 31/12/05 the same issue date.
You could then absolutely rely on everybody, despite numerous reminders, to leave it until the last minute, then off we go around the merry go round again.
I expect that scheming to "rip you off" is the last thing on their minds right now, or ever for that matter.