Well, to be fair, it gets easy to use more than one form of your name if you aren't careful: while I put 'Jonathan' on most official forms, if it's pertaining to university I use 'Jonny', because, er, I've not got around to telling them that my full first name is Jonathan. Or that my middle name exists. I should probably get around to that at some point. Also, there's a few places where I'm down as "John" because someone misheard "Jonny", and had been using that for a while, and I wanted to spare them the embarassment of finding out they were using the wrong first name, especially with a confusing last name that I occasaionally let the spelling go on, because it's easier. So that's how it can happen that someone uses more than one name. And once you start, it can kinda snowball. But I appreciate that it makes your sort of job harder.

And it's always amusing to read your posts like this, don't feel guilty.