What is affect of --polymaxzoom ? is more zoom level value make route calculation faster ?

According to below command:
_`python ./scripts/build_valhalla_package.py --id $AREA --poly $AREA.poly --polymaxzoom=14 valhalla_tiles ${OUTPUT_DIR}/${AREA}/${AREA}.vtiles`_

What is affect of changing the --tilemask? There is also a harcoded tile_mask=10 in the scripts.

I want to speed up route calculation and file size is not my concern.

I have generated the Iran and Russia map packages separately with maxzoom=11
The route calculation performance of the Iran map is about 3 seconds in the worst case.
But in the Russia map for two points close to each other with a distance of 500 meters from each other, the calculation time takes 3 seconds in the best case.

How can the route calculation time be improved?