Why can't I get a TIN taxpayer number in Thailand until after the tax year ends?

I went to Thai Revenue department (Chalong) earlier with all the correct paperwork and they told me I couldn't get a TIN taxpayer number until after the tax year has ended. Is this normal? (doesn't sound like a smart way of doing things)

Edit: Sounds like it's just another case of ineptitude and I wont be able to sort this out at the office. Does anyone know an agent that will get me a TIN now for a decent price?

Edit 2: Went again armed with a wall of pre translated text from my accountant everything everything, and despite this I had to spend a whole hour repeatedly schooling them on the law, accounting and the revenue code, with them accepting my arguments each time and then changing the subject and perpetually and erroneously inventing new things I'd need to get the TIN, and after an hour of debunking and debating with 4 staff they just went right back to the start as if we hadn't spoken yet, and at that point I had to just throw in the towel because it was obvious that we weren't going to get anywhere. The principal lady that dealt with me was incredibly smug and rude and childish, and it was very obvious that she simply didn't want me to succeed.. the problem wasn't my paperwork, logic or position; it was her/what she represented. Politeness got me nowhere.