High cpu usage with using one AU MIDI PLUGIN


high cpu usage in cubasis, when i use AUmidi plugin , compared with other daw apps like auriapro.

1, create one midi track
2, in midi effect select one AU MIDI for example ( Audio veek : midi key zone ) .
3, when i play one note , cubasis cpu metering, shows up to 25% - 30% of cpu usage.

Does this CPU usage for just one track and just one AU midi do not look a lot ?
I tested same preset with auriapro, it shows just 7%-8% of cpu usage.

Ipad air 2
Cubasis 2,7
IOS 12,1,1
Audio veek latest version

Best pejman