consistent with generally accepted accounting principles.$)1)$ Recognizing a receivable and revenue when the contract allows for invoicing of the customer. $2)$ Use of estimates to accrue for the completeness of expected after$-$sale expenses related to revenue recognized. $3)$ Determination of separate performance obligations for contracts related to customers, with recognition of revenue, occurring based on the satisfaction of those performance obligations. $4)$ Estimating the allowance for doubtful accounts and related bad debt expense based on the historical experience, because it is reliable and measurable, without regard to considering current economic conditions.