The reason any other platform won’t have the same result is because they’re only looking at average power over the activity… they aren’t accounting for the order in which the work was performed.
I used the workout designer to demonstrate why this is important. I used 2 interval steps to set up the demonstration: 20s at 2 min power and 25 min at 105% Threshold power (using my specific signature - I probably should have used MMP for both so they’d apply equally to all athletes/signatures). The average power for both efforts (and total work performed) between the two are identical:
However, if we look closely at the first setup, which is 20s hard effort followed by extended effort above threshold, the interval ends with MPA close to, but not quite reaching, MPA:
On the other hand, if we model riding above Threshold for ~25 min and then do the 20s effort at 2 min power, we can see that this effort wouldn’t be possible, because of the order in which the work is done. MPA is already too depleted when the hard effort is started to achieve this effort, even if it has the same average power/work performed as the first set:
Most other platforms might simply ~95% of your 20 min average power from that effort, but what that fails to account for is at the very end of your race, your MPA still needed to be high enough that you could ride at 400 W for ~30s or so. If your threshold was lower, then your MPA would already be too depleted for you to be able to achieve an effort of that magnitude.
Hope that makes sense!