Corporate (Mis)Communication

Recently, I had to correspond with a couple of HR people about my doj of my project and to my HOD regarding my semester exam. Can u trace a pattern?
If u r one of those enlightened ones, take care in your future communications with these "big ppl" :)

Scene 1:

Me(in mail):

Sir,
I'll be ready to join ur esteemed org after 17th dec as my exams get over by then.
bla bla bla...

Reply:
You can join the team on 17th dec.

Me:
??!!??

*******
Scene 2:

 Me: Mam, as i've my professional exams from 10th dec, is it possible to schedule the semester exams before 10th decemeber so it doesn clash?
HOD: Sure. So you want the semester exams to get over before 10th is it?
Me:(sounding relieved that she caught on so easily): Yes mam. I cant afford to miss either of these exams.
HOD: sure. I'll look into it.
----------
After a week,

Time Table for End semester Examination: Starts from 2nd dec and the last exam is on....
10 dec - Economics

Damn..
Rushing to HOD
Me: Mam, You said it wouldnt clash. I just saw the time table and its getting over on 10th and the same day, my other exam starts. Same timing too.
HOD: What? you said 10th december. Its getting over on 10th right?
Me: Yes mam, but I said my exam starts on 10th dec. Now its clashing.
HOD: its ok. Write that exam alone as supplementary. Its not a big deal.
Me: ??!!??
*******


Well. Whats with these ppl and dates? Why is it that they simply look at the date and completely miss the preposition before it? Is this corporate communication?