You are right, QBO can act quite differently and even on its own double enter transactions as can be seen in some recent questions. But once a transaction is actually "in" your books as opposed to bank feeds which are pending and For Review, then if it is income or expense it will be in P&L.
What will not be in Cash Basis P&L will be invoices and bills which have yet to be paid. Since they are not paid there is no banking activity, but they would appear in Accrual Basis P&L - that is the biggest difference between accrual and cash.
Underneath every version of QBO and QB Desktop , quickbooks is in fact accrual based accounting - it is the choice you make of how the data is reported to you that makes the difference.
