Normally when any assumption is changed, the results and charts will be instantly updated, but perhaps that doesn’t seem to be happening.
The first step is to see if “Calculations” are set to automatic or manual. Excel allows users to disable automatic calculations when a model takes ages to recalculate and waiting after every cell change becomes annoying. In the menu bar at the very top of the Excel application where it says “File Home …” go to “Formulas >> Calculation Options” and make sure “Automatic” is ticked. If for some reason you need to keep calculations set to “Manual” then press the “F9” function key to recalculate. There is also a “Calculate Now” button in the “Formulas” menu.
Not every line in the Financials sheet is affected by every assumption, so if you think something is not updating, then a good one to check is the final year cash balance (as most things will flow through individual years, AND over time to affect that single cell). So try changing the assumption again and compare the before and after cash balance.
Some assumptions have “Start Date” and “End Date” type options where you can enter values like “Jan-2024” to only include results from this date. Check that the section you think isn’t working hasn’t had these dates changed to disable the month or year value you are struggling with. Note that some assumptions will also rely on earlier ones with date ranges. For example if you change the start date for when new customers are acquired to be the Jan-25, then no matter what you set the price per customer to in a later section, no revenue will be generated in years before 2025.
Similar to the above, assumptions that use earlier assumptions as their input will not have any impact if those earlier inputs are set to zero, as any value multiplied by zero is always going to be zero.
Some assumptions will not impact the month you are changing. e.g where payments from customers are delayed, only later months in the cash flow will be affected by a changed price or quantity sold, whereas the P&L will be impacted in the same month. Similarly for staff bonuses, you can change the frequency and timing of payments, and these will affect cash flow, but the P&L will use the accrued bonus amounts in every month, so will be unaffected by those timing changes. These examples are consistent with IFRS and GAAP accounting standards.
Finally, it is also possible (although unusual) that some assumptions only generate KPIs for information rather than impacting financial performance, so check the notes and instructions in that section to see if that is the case, and check if values in the Other Metrics sheet or Dashboard sheet are changing to confirm this. Quick tip, is to highlight every KPI output in the section at the top, and note the sum in the status bar at the bottom of the Excel application, then see if this sum changes when you change your assumption value. Then you know it is affecting at least one of the KPIs, so is probably working as intended.