I think the bumping score start to be recorded from the moment the thread is moved to that section. All the previous comments/bumps are ignored.
No, every thread forum-wide has a bump score, with the same mechanism of operation everywhere. Moving doesn't affect it. The only per-section differences are UI-related:
- "Bump" links are displayed in targeted sections.
- The default ordering is different in targeted sections.
It's even possible by playing around with URLs to superbump any thread, but since the default ordering doesn't take this into account, it's pointless in non-targeted sections.
When a topic is moved, bump-wise it's as if the topic always existed in the destination section. There's no advantage to bumping in one section and then moving it to another.