12686 H & 12687.29 H with a symbol rate of 2400 (which could give a 2-3 MHz variance anyway!)
are the same freq. No correction made!
Different LNB / Dish / Cable / Receiver tolerances will always give slightly different freq's
Nothing wrong with the info in the first post whatsoever. If Say 12696 H had been posted in error then a correction would be needed!