Give me specific quotes from command briefs and then I'll believe it. After reading the command brief from "Their Finest Hour", the main concerns seemed to be that the Shivans might be able to jump without nodes, and that they really didn't know exactly how big the Lucifer's explosion was. In fact, I suspect that they would have used more meson warheads than they thought they would need, just to be sure as this was a critical operation.
So you read the command briefings anyway and want quotes?
"A Great-War-era destroyer, the GTD Bastion, will contain multiple meson warheads that will detonate inside the node. Scientists beilive an explosion of sufficient magnitude will cause the node to collapse, as evidenced by the destruction of the Lucifer 32 years ago."
I looked through all the command briefings up to the mission where the Bastion goes into the node, not one word of it saying that it wasn't or wouldn't be as powerful as the Lucifer's explosion, but instead they're saying that if one destroyer exploded inside subspace and collapsed nodes, that it should happen again if they
make a destroyer explode in subspace.