I have the "maths and Excel skills" you need. I designed dashboards, reports and interactive spreadsheets and managed databases for twenty years at a leading multinational. Now work from home in the UK across five freelance sites, with good reviews from international clients who have utilised my expertise in VBA Coding, Formulae and Conditional Formatting.
Without knowing how MANY formulae you need or how much research is needed to understand what formulae are needed to replicate the reports, my bid allows five hours' to produce the formulae.
I would normally provide samples to let you judge my Excel skill for yourself, but as you made this a "restricted" project I can't send an attachment unless you send me a Private Message first.
I can work under a Confidentiality and Non-Disclosure Agreement if required, and start as soon as you pay the fee into the site and send me your existing material.
Hope you find this of interest and look forward to hearing from you
Bob Allen-Turl