Well, that seems to fit pretty neatly with Lord Bathurst's figure. I think that he would be talking of raising a new first battalion (does anyone know what actually happened when they enlarged the army in 1823/4?), so some of those debatable costs would have been incurred, but the reduction in the number of rank and file would have reduced the overall cost. You got, very roughly, 60 per cent of the men for 75 per cent of the cost - sounds like a typical cost cutting, economizing move, doesn't it? Still, as Wellington argued at the time, a larger number of smaller battalions were of more use in organizing reliefs of colonial garrisons and reinforcements to troublespots, than fewer, larger battalions (it would be different in wartime).
Rory