In that Trance Octaves preset, you may be hearing the difference between the delays (in milliseconds), and the independent MOD SPEED setting (in % Hz.). And when you tap in the tempo, both Delay times will change, but the modulation speed remains unaffected.
See if you hear better results with this variation on the Trance Octaves preset. It will conform mod speed and delay time to sync while you tap in different tempos.
