I haven't read other responses, but here's my question:
If your relationship is really good, why should something like this put a huge hole through it?
I just don't understand. Perhaps he's being selfish. Perhaps he's stressed about the move and wants to prep in advance, get as much settled in before asking for the help on Saturday. I have to tell you, when I move, I get everything done and packed way in advance because I hate to inconvenience people. Anyways, to me he sounds distracted and worried.
Tell me this, though... in your relationship, have you ever been a self-absorbed daughter when you were stressed? I know I have. :) What's more, when my dad gets self-absorbed because of transitions, I just give him some grace. We all go through seasons. This season has bad timing, right? What you are wanting is for him to show some interest in you and your life, and he's consumed with his own at a time of transition, and it's creating some tension.
I would say this: either give him some grace about this and just help him move, or maybe admit that sometimes he's selfish and it just really bugs you. But I think NOT helping him because of this is really, really immature, esp. if your husband has already committed to it. Chances are, too, your husband might not want to get in the middle of this and let your dad down because you are momentarily upset. I know you wanted to share your daughter's birthday and your trip news with him; remember that there will be more birthdays and more trips.
You can choose not to get upset, too. He'll likely be more interested in other things as he gets settled in. Not saying anything about it right now also leaves the door open for a better conversation with him about this after the move, when you feel less upset about it and can give him some constructive advice or talk about your feelings with some objectivity. Then, you can tell him how you felt and he'll likely be less defensive about it, but more able to listen because you both won't be so stressed.
Just my perspective.