Adventists today when calculating the 1844 date use Daniel 8;14 which gives 2300 days converted to years.
The starting point for this calculation is 457 bc which is also the starting date for the prophecy in Daniel 9 which gives the prophecy when Jesus was crucified and Stephen was stoned. There is a verse there somewhere which Adventists use to give the meaning that the time period in Daniel 9 was cut off from the longer period of the 2300 days.
The other interesting point about Millers reasoning is his calculations were made from various parts of the bible to arrive at 1844 and he believed a number of even weak points would strengthen his point of view. A strange concept indeed.
This doctrine is still taught by the right wing SDAs but is almost forgotten by the theologians because it just can't be proven.