Accounting Program Print Routine Fix Fix VAT Invoice Calculation Bug
Budget: $10 – $50 USD
The invoicing module in our custom-built accounting program shows the correct figures on screen, but when I enter a selling price that already includes VAT the printed invoice miscalculates the net and VAT amounts. Prices entered exclusive of VAT work perfectly, so the issue is isolated to the inclusive-VAT branch of the print routine.
What you need to know about the environment
• The software was developed by a professional firm that has since gone out of business, so it is effectively a proprietary, custom solution.
• I only have the compiled .exe — no original source code or documentation.
• The underlying language or framework is unknown to us.
What I need from you
1. Diagnose the section of the executable (or its related libraries) that performs the VAT split when the user chooses “price incl. VAT”.
2. Patch or otherwise modify the logic so the printed invoice shows the same net amount and VAT that appear on screen.
3. Supply a tested, working executable (or a drop-in patch/loader) and brief instructions for installation.
Acceptance criteria
• For any price entered inclusive of VAT the printed invoice must display:
– Net amount = (Gross ÷ (1 + VAT%)) rounded exactly as on screen
– VAT amount = Gross – Net, again identical to on-screen values
• Prices entered exclusive of VAT must remain unaffected.
• No other program features may break as a result of the fix.
If reverse-engineering is required, please confirm your approach and any tools you intend to use so I can approve them beforehand. Let me know how quickly you can turn this around and what you would need from my side to get started (sample invoices, VAT rate settings, etc.).
What you need to know about the environment
• The software was developed by a professional firm that has since gone out of business, so it is effectively a proprietary, custom solution.
• I only have the compiled .exe — no original source code or documentation.
• The underlying language or framework is unknown to us.
What I need from you
1. Diagnose the section of the executable (or its related libraries) that performs the VAT split when the user chooses “price incl. VAT”.
2. Patch or otherwise modify the logic so the printed invoice shows the same net amount and VAT that appear on screen.
3. Supply a tested, working executable (or a drop-in patch/loader) and brief instructions for installation.
Acceptance criteria
• For any price entered inclusive of VAT the printed invoice must display:
– Net amount = (Gross ÷ (1 + VAT%)) rounded exactly as on screen
– VAT amount = Gross – Net, again identical to on-screen values
• Prices entered exclusive of VAT must remain unaffected.
• No other program features may break as a result of the fix.
If reverse-engineering is required, please confirm your approach and any tools you intend to use so I can approve them beforehand. Let me know how quickly you can turn this around and what you would need from my side to get started (sample invoices, VAT rate settings, etc.).