TT should design the software to only require data to be entered once, i.e. "A". If data is computed because in another schedule "A" is used to determine a portion of "A" then the program should collect where "A" was entered and bring the value forward and used to compute the fraction that is required. The program should then adjust the figures where total amounts were entered and compute the new figures. If the user files the forms in reverse order or what ever order they so desire TT should be smart enough by checking applicable entries if boxes contain dollar amounts and warn the user that a possible double entry was made. A simpler way would be to provide instructions from when the user launches the program a logical flow diagram on how TT expects the user to fill out the forms. Yes it will make TT a bit more complicated for some people but errors must be avoided. I hope I got my point across.
