Multi City booking - same city more than once?
 

I was doing a few searches on Google Flights and and put in two return trips between the same cities as four individual flights as a multi city not really expecting it to work, but it actually gave me a price. The only option it gave to click to book was via British Airways. When it took me to the BA website it gave the following message:-

Error

• Your itinerary includes more than one flight(s) between the same cities. Please remove the repeated flight(s), even if they are on different dates, to get a quote. You will need to make a separate booking for the additional flight(s).

If I were to book as two separate bookings the price is of course higher.

Is it just the website that won't allow more than one flight between the same cities, and is it possible to book if I phone BA, or is Google Flights just giving me a phantom price for something that can't be booked?

Not sure you can do that via ba.com, anything fiddly I just call Amex (other travel agent should work too) and get them to book the itinerary for me.

Fwiw last time Amex even found better pricing than ITA matrix showed, that was a TP run with three back-to-backs in it: LGW-JER-LGW-AMS-LGW back in March when there were some really cheap CE seats going.

Depends on your itinerary, but I managed to book INV - LHR - HEL - LHR - OTP - LHR - SOF - LHR by just putting something like INV - HEL; HEL - OTP; OTP - SOF; SOF - LHR in the multi-city booking, and it came up with the pairs of flights I needed.