Why does DeskOps say a job's margin is unknown?

Because revenue landed and no costs were attached to it. A job with money in and nothing out is not a 100% margin job, it is a job whose costs DeskOps has not been told about — so it says unknown rather than printing a number that would flatter you into a bad decision. Open the job, choose + Attach a cost to this job and pick the expense, and the figure appears. A cost counts wherever the job's profit is shown whether you attached it to the job or to its invoice: a receipt attached to the job from Expenses is in that invoice's Job profit card too. The one exception is a job that more than one invoice bills, such as a deposit and a balance — a cost attached to that job counts once, on the Jobs board, and the invoice card says so instead of charging it against both documents. On Types, a margin covers only jobs whose money and costs are both known; a paid job with no costs, or hours with no pay rate, is left out and named.