How are the amounts and expenses that were not accounted for in the first meal calculated, given that the partner was recording goods and full profits in his name unintentionally or unknowingly, and that the profits range between 10-20% for each partner?

The aforementioned company is a type of Mudarabah (profit-sharing partnership), where the questioner pays his money to the shop owner for him to invest it in machinery, in exchange for fifty percent of the profits. This is permissible if the shop owner's capital is known before mixing.

Mudarabah expenses and costs are first deducted from the profit. If there is no profit, then they are deducted from the capital. However, it is not permissible for the shop owner to take a specific amount from the capital before knowing the actual expenses, because this invalidates the Mudarabah if one of the partners is allocated a known surplus in dirhams.