Why does route xl change the location names

When i put ythe addresses in sometimes after creating the route i find the address names or even worse the postcodes have been changed

Your input is send to Google for geocoding. That is finding the position on the map. If Google does not recognize the address as such it may be changed to something else. We use this address for the route optimization. However the location should always show the name you used.

You can prevent changes by using the correct full address. For example:
277 Bedford Avenue, Brooklyn, NY 11211, USA

If you use the search box on the top left, the autocomplete feature will suggest the address as Google knows it.