We are both making assumptions here. Like you said, depends on masses and distances. And no one is going to make all the calculations to check everything.
You assume the ship was at a stable orbit over the dreadnaught. I am assuming that the ship, so close to a much bigger ship with much greater mass, must have been actively fighting against its gravitational pull, and that the bombs, once released, wouldn't be able to.
Of course it's not realistic. The gravitational acceleration was like it'd be on Earth, when in reality it would be much lower.
But in the end, in a series with laser swords, and hyperspace travel, and the force, "big thing in space attracts smaller things" isn't preposterous, even if they do take some liberties with it.
And, finally, the reason so many people immediately reject the idea is because in their minds:
Earth=Gravity, Space=No Gravity
Instead of:
Every mass has a gravitational pull, the bigger it is, and closer you get to it, the stronger it gets.