An interesting thing about break-in - especially if you've never heard the gear before - is gauging when it is complete. How long does one go without hearing changes before assessing break-in is finished? If one knows a fully broken-in piece, then its easier to gauge a unit has not yet met the known expectation. There's also the question of relative change across time. My experience with the MP-1 found the majority of change in the first 120 hours and I agree that further changes occurs after that, tho not, imo, to the same degree (however one measures that!).
Likewise, being away from listening in chunks of hours while break-in continues to run may better lend to hearing changes across those hours than continuous exposure for the same period. Re-acquaintance and one's sonic memory may also play a role in the perception of change.
Wrt loading, the MP-1 is a wonderful instrument for hearing differences in load resistors.
Rgds,
Tim
