Zwift step test too high vs TR?

[CrunchyGears]

@SpareCycles

Shorter stages or higher steps will produce a higher peak power and higher threshold estimate. Longer stages or lower steps will produce a lower peak power & threshold.

Assuming both tests use the same percentage of the final step to set your FTP, which I doubt is true. Both of those protocols may work fine if they are calculated differently to end up at a similar result.