When using an Amex 2-4-1 Companion Voucher the flights offered are not always the same as are available for BA Miles redemptions only. I have found in the past that flying from my regional airport to LHR and onward using BA Miles usually gives me a reasonable choice of flights down to LHR. However, if I try and do the same using miles and my Amex 2-4-1 the number of available onward flights from LHR remain the same. However, the number of flights from my regional airport usually reduce from those available were I to use BA Miles only. In some cases it has been necessary to travel to LHR the day before when using an Amex 2-4-1 as their was no domestic flight availability the same day as my onward travel. However, using BA Miles only there would have been domestic flight availability.