raid0 hashing funtion

Neil Hello
I am reading the raid0 code, and I do not understand what is the
rational behind this hashing and spacing ?
I am asking because I am working on the chunk size restrictions.
in raid0_make_request the zone calculation is as follows:

      {
              sector_t x = sector >> conf->sector_shift;
              sector_div(x, (u32)conf->spacing);
              zone = conf->hash_table[x];
      }
        while (sector >= zone->zone_start + zone->sectors)
                zone++;

I replaced it with the code :
        zone = &conf->strip_zone[0];
        while (sector >= zone->zone_start + zone->sectors)
                zone++;
and all is fine .  why do we need the hashing/spacing complication ?
thank you
raz