A master has two colour machines with a minimum volume for both black and colour. All unders and overs are clawed back at the current rate (ABC). There is a minimum of 10,000 pages for black and 2,000 pages for colour.
First machine has opening balances of 25,000 black and 10,000 colour, with reads received of 29,000 and 11,500. The second has opening balances of 50,000 black and 8,000 colour, with reads received of 53,000 and 9,000. Once jobs have been created for the two children and the master, they will appear as follows:
We can see that there were 3,000 unders pages for black. As there were colour overs, there are no amounts billed on the master, and the 500 overs are just tracked. The total for the master as a whole is 10,000 X 0.01 + 2,500 x 0.1 = $350.00 ex tax.
The following month, the first machine receives reads of 36,000 (7,000 pages) black and 12,300 (800 pages) colour. The second machine receives reads of 58,000 (5,000 pages) black and 9,400 (400 pages) colour. The following jobs are created:
We can see that some of the unders charged in the first month for the black meter are clawed back in the second month, and that all of the overs charged in the first month for colour are clawed back in the second month.
The total for the master as a whole is 12,000 X 0.01 + 2,000 X 0.1 = 320.00, less the 2,000 black overs, less the 500 colour overs. When reducing overs, we:
▪reduce unders (if it's a master),
▪increase standard billing.
For black we add (-2,000 x 0.01 – 2,000 X 0.01 + 2,000 X 0.01) = -20.00
For colour we add (-500 X 0.1 – 500 X 0.1 + 500 X 0.1) = -50.00
Overall we bill 320 20.00 – 50.00 = 250.00 ex tax.