Battle Calculator - Is it always correct?

[Console_Cowboy]

I have to make a decision: should I wait for more troops or siege an enemy with my current force.  Morale is the determinent of victory.  The battle calculator determines I am victorious under both scenarios.

Scenario 1:
By plugging in my current force (vs. my opponent) into the battle calculator, the statistics read as follows:

MORALE
at end of field battle: 94 after 6 rounds
at end of siege: 30 after 19 rounds
after garrison battle: 26 after 2 rounds

Scenario 2:
By plugging in my current force plus an increase due in a couple of hours (vs. my opponent's current force) into the battle calculator, the statistics read as follows:

MORALE
at the end of field battle: 95 after 6 rounds
at end of siege: 43 after 16 rounds
after garrison battle: 39 after 2 rounds

What's your advice?  I know about morale and it is better to have a higher morale. But is there a reason for waiting?
Moderators, is the battle calculator ALWAYS right?  Does it mean I am victorious under both scenarios?

[Console_Cowboy]

Assuming I can send two attacks, what will happen if I send my current troops now AND send 550 more troops after they finish their training and I activate them?  Will the new ones join the battle as reinforcements?

Or will 200 troops be faced with taking down a fortress alone, while the first group is returning home? 

I am trying to shave off some time.    And hoping the battle calculator is better than a magic 8-Ball in prediction.

[Console_Cowboy]

Thanks!!!

+1 for both illuminating answers.  I thought it was risky but after the field battle there is no one inside the fortress and the task is just to bash it down. So I thought, maybe, the calculator was taking this into account - the risk to morale being troop boredom and attrition through mutiny.

Apparently not.  And thanks for the advice on averaging.  I never would have thought of that one.  +1 for that answer too but someone else will have to give that + to you. You got my max for today.

Respect!