Also expensive to me....but your paperwork won't be ready untill you fill up with your flight day and number. And careful cheating them, your visa can be refused.
Any problem? Phone them !!!
If there is any problem after sending all docs, they will tell you and will try to help you to find a solution.
After, few months living in Thailand, I understood that, no matter "why", just they want that way, so....just do it the way they want. Filling that formulary was also a nightmare for me, and I couldn't stop thinking about....why this ? .....why that?.... What if this?.... what if that?.... don't ask yourself why, why, why....just look solutions.
You will do everything ok, and no problem with your visa !!