I can do exactly what you need. I'm a computer science professional with a PhD degree and extensive experience in financial and economic math including all sorts of formulas involving accrued interest calculations and debt repayment, as well as in Excel formulas, macros, and VBA. I've done a lot of similar work. Please see reviews on my profile. It would be my pleasure to do your project. Please let me know the details.
Please have a look at some Excel projects I've done:
https://www.freelancer.com/jobs/php/Need-excel-plugin-convert-USD/
https://www.freelancer.com/jobs/Excel/Need-covert-very-large-dat/
https://www.freelancer.com/jobs/Excel-Mathematics/Convert-math-proofs-Excel-formulas/
Here are some Computational Finance projects I've done:
https://www.freelancer.com/jobs/Excel-Mathematics/Convert-math-proofs-Excel-formulas/
https://www.freelancer.com/jobs/Matlab-Mathematica/Write-some-Software-Matlab-Solving/
https://www.freelancer.com/jobs/Matlab-Mathematica/discrete-optimization-using-mathematica/