API Arrival Times vs Web Front End Times

Hi, I’ve just started using the API’s Tour method to work out how long a whole route will take.
Using this Json:

[{“address”:“BH1 3NA”,“lat”:“50.722324000”,“lng”:"-1.864432000"},{“address”:“BH2 6EZ”,“lat”:“50.721961000”,“lng”:"-1.878005000"},{“address”:“BH14 9LP”,“lat”:“50.723740000”,“lng”:"-1.930573000"},{“address”:“BH1 3NA”,“lat”:“50.722324000”,“lng”:"-1.864432000"}]

it returns:
{“id”:“gCT6AllH”,“count”:4,“feasible”:true,“route”:{“0”:{“name”:“BH1 3NA”,“arrival”:0,“distance”:0},“1”:{“name”:“BH2 6EZ”,“arrival”:2,“distance”:1.3},“2”:{“name”:“BH14 9LP”,“arrival”:8,“distance”:6},“3”:{“name”:“BH1 3NA”,“arrival”:15,“distance”:11.4}}}

The arrival time on the last one is 15, so my assumption is that it will take 15 minutes total to do a complete route through all 4 locations. However if I put the postcodes of each location into your websites front end then the total time to do a route works out to be 25 minutes.
Is there something I’m missing when using the API? Perhaps a missing parameter or something as I would have thought that it should come out exactly the same as the web front end on your site?

Thanks

Nevermind, have resolved it. The website was including a 5 min duration time.
Thanks.