We seem to be a bit confused over the various parts 🙂
Parts (a) and (b) are purely discussion (why overhead allocations will have changed, and then about implementation problems).
Part (c) asks for the cost per unit using machine hours to absorb the overheads. This is traditional absorption from Paper F2, and I assume you are happy with that.
Part (d) asks to the cost per unit using ABC and I assume that it is this part that you have problems with.
You will know from my lecture that there are two ways of getting the same answer (and the examiner does show both ways in his answer) but that the easiest and best way is to split the overheads in total between the products and then having got the total overhead for each, divide by the number of units to get the overhead cost per unit.
As I wrote in my previous reply, the cost of each QC inspection is 3,340 and the cost of each production run is 3,250. The question tells us the property costs are to be absorbed on machine hours, and they come to $18 per hour.
So the total overheads for CB are as follows:
QC: 180 inspections x $3340 each time = 601,200
Set-up: 4 setups x 3250 each time = 13000
Property: 100000 hours x $18 = 1800000
So total overheads for CB = 2414200
The production of CP is 1,000,000 units, so the overhead cost per unit is 2414200 / 1000000 = $2.41
(Same approach obviously for TJ)