As written in DGR 18.104.22.168.2 Step 6 (i), the DGD should show the Net Quantity of Explosives including its casings, and the Net Explosive Mass (NEM) for each package.
However, if the DGD is made up in a clear manner showing the Total NEM quantity of the total 24 packages, such entry will not endanger the safety of the aircraft, and should not be rejected particularly when the shipment is going to be carried by one airline all the way to its destination.
You May wish to advise the shipper to show the NEM per package for the next shipment. If interline transfers are involved, to avoid unwanted problems en route, it will be better to have the entry corrected to show the NEM for one package. There May be airlines who strictly follow the rules.