Maybe 90% was a bit of hyperbole, it's roughly 70-80% on multi-spool engines. The point being it's not a slow idle like a gas engine, the bearings are being wrung out even at idle. There is literally no "bottom of engine" for the oil to collect in, as the dry-sump system evacuates oil from the bearings as the engine turns. The engine has rotated hundreds or thousands of times by the time it even lights off.