{"id":"cs-invoice-difference-explained-math","audience":"executives","category":"support-work","technique":"verification","track":"support","level":"advanced","title":"Explain an invoice that differs from the quote, with proration math","free":false,"task":"Explain the invoice difference to the customer's finance lead in exactly three lines starting \"Quote:\", \"Added seats:\" and \"Invoice:\". Show each as math. The added seats are prorated by days in the month. Plain text, under 60 words.","materialLabel":"Your material (attached to your prompt automatically)","material":"BILLING EXPLANATION, Halden Co (November invoice)\nQuote: 50 seats at $90 per seat per month = $4,500 per month.\nChange: on Nov 16 the customer added 5 seats. November has 30 days; the new seats were active for 15 of them (Nov 16 to Nov 30).\nProration rule: added seats are charged for the days active: seats x price x (days active / days in month).\nInvoice: $4,725.\nHelp: 5 x $90 x (15 / 30) = $225. $4,500 + $225 = $4,725.\nFinance lead's email: 'Why is the invoice $225 higher than the quote? I did not approve more seats.' (Seats were added by the admin, Lars.)\nDo not blame Lars. Say the invoice follows the added seats.","rules":[{"type":"plainText"},{"type":"maxWords","max":60}],"mistakes":[{"title":"Charging the full month","why":"The AI charges 5 x $90 = $450 for the added seats.","fix":"Say: \"Prorate by days: 15 of 30.\"","checks":["r1"]},{"title":"Blaming the admin","why":"The notes name Lars.","fix":"Add: \"Do not blame anyone; say the invoice follows the added seats.\"","checks":["r2"]},{"title":"No math or wrong layout","why":"The AI writes a paragraph.","fix":"Name the three labels and show each as math.","checks":["r0"]},{"title":"Getting markdown back","why":"AI adds bold and headings by default, which show up as stray symbols where this is pasted.","fix":"Say \"plain text, no bold, no headings, no asterisks\".","checks":["plainText"]},{"title":"Trusting the AI to count words","why":"AI is bad at counting and usually runs long, so a vague \"keep it short\" lands well over the limit.","fix":"Cap each part instead of the total, for example \"each line under 15 words\".","checks":["maxWords"]}],"promptHints":[{"label":"Asks for plain text","patterns":["plain","no bold","no markdown","no formatting","no headings"]},{"label":"Sets a length limit","patterns":["\\d+\\s*words","word (limit|count)","under \\d+"]},{"label":"States the proration rule","patterns":["prorat","days","15 / 30"]},{"label":"Names the labels","patterns":["quote:","added seats:","invoice:"]}],"hint":"Invoice explanations must show proration math and stay neutral. State the rule, the three lines and the no-blame instruction.","rubricLabels":["The output is exactly three lines starting Quote:, Added seats: and Invoice:","Quote shows 50 x $90 = $4,500 and Added seats shows 5 x $90 x (15 / 30) = $225","Invoice shows $4,500 + $225 = $4,725, and nothing blames Lars or says the customer made a mistake"]}