[PeterisP]

What mathematical models? For your company financial assumptions and forecasts you generally need, in essence, the sum(...) function, percentages and multiplication, repeated ad nauseam, and if any of your formulas even have space for 'not easy to spot' bugs then the bug is in thinking of making such formulas in the first place.

Your spreadsheets would be big because of quantity of different things included, not because of complexity of those things