You told @Abeiku that you did not have Production in progress among your balance sheet accounts. But in the balance sheet you showed (as at 31.03.2020), it turns out you suppressed zero-balance accounts. Your chart of accounts shows that you do, in fact, have such an account.
Production in progress is created automatically when you have insufficient quantities for a production order. This was probably the cause for any sales invoice that does not show up correctly in INVENTORY - COST. The cost has not been transferred yet, because you do not own sufficient quantities of all items necessary to complete the production order. Read the Guide: https://www.manager.io/guides/29016.
An alternative is that, however you acquired the components that went into a finished inventory item, you incorrectly allocated no cost to them.
As I said before, you need follow an inventory item completely through your workflow, understanding how it was acquired, at what cost, and how it was used or sold. So far, your illustrations have shown one of two things:
- Some show Manager is functioning correctly based on inputs you have made
- Others show you are not making inputs correctly