Sounds highly irregular...if that is correct your annual stipend would be more than 28k (about 8K more than a new post-doc and they’d have to pay tax on it!). It's worth checking with someone at the Uni, you don't want to spend it and then find you have to pay it back. However, if you find it's all yours then great, go out and party! [And then tell me where you are studying so I can try to get a 2nd PhD there, more profitable than post-doc-ing! ;o)]