Regarding the subject of going into extension in accordance with CAA CAP747 GR No 24, I interpret:
"The engine being inspected in accordance with paragraph 4 in order to assess its
condition immediately prior to the increase, and subsequently at 100 hour or yearly
intervals, whichever occurs first."
- as meaning at TBO the engine is inspected and then monitored at 100 hr/12 month intervals for condition, oil leaks, oil consumption and cylinder compression.
I do not believe any previous oil consumption figures are demanded prior to TBO although obviously the more info the better.