Well, put me down as believing that it's less of a reality violation
to charge both the attacker and the defender the time for the combat
than to only charge the attacker.
In the case of kamikaze attacks (1 noble vs. a megastack), it's absurd
to believe that a head-on attack would cost much time at all, but
if it's examined as 'one noble is willing to die or be captured in
order to delay someone's movement' it's not unreasonable. Trap setting,
various sniping attacks, etc. would occupy the time, and the time
for the other stack to avoid said traps and/or stop them (by removing
the pest) would be explained their delay.
It's not perfect (it doesn't address why 1 noble attacking 1 noble
takes 1 day, and 10 nobles with 1000 peasants vs 10n & 1000p takes
one day, but it would, I think, improve the reality-matching of the
game.
--kdc