Well, Murray, if that is so it points out another problem.

The strings are always wider apart at the saddle than at the nut so in the absence of a compound radius fingerboard then either the fret heights will change to create a compound radius notional playing surface, or the playing clearance at the frets will not progress correctly up the neck - I think it will be the bottom and top E will find (dis)proportionately greater fret clearances as you progress up the fingerboard.

I almost can't believe that to be the situation.