activemobility
Welcome to the MYOB Community Forum, I hope you find plenty of useful information.
Inventory can be a bit tricky at time.
Any changes you make will not be relected in any transaction already done only in new transactions.
If you change something and want it to be reflected in previous transaction then you must first delete those transactions and then after making the changes re-enter them.
If you manufacture something then you would use some kind of materialsa to make it. To correctly set inventory up to reflect the use of those materials you need to create autobuild item for the new item and use the costs for the materials to generate the cost of the new item. If that item is then going to be used in another item you would then create another autobuild for that item as well.
Normally to get true values for built items the Standard cost is not used rather the last purchase price is used and that get entered automatically when you purchase the raw materials.