Labour rates in project accounting should have start and end dates

Our financial year runs October to September. Yet we give pay rises in January each year as it takes a while to wrap-up year-end, work on the budget etc. In project accounting there is only one labour cost rate available in the "Hierarchy". For example, we have several people in a group which we've called "Engineers" and last calendar year, we had an approximate rate of £20 p/h. We don't use actual costs despite having Sage 50 payroll 'joined up' to Sage 200 because then it's too easy for people to work out what people get paid which is always sensitive. But after re-assessing this for pay rises for 2024 due to cost of living increases etc, we've decided that £30 p/h is more appropriate on average. But there is no way to say that £20 p/h labour cost rate applies between Jan-Dec 2023 and the new rate of £30 p/h applied Jan 2024 to Dec 2024. This then affects the actuals and causes differences when we compare our project budgets to actuals because Sage can only handle the one labour rate. I've shown an example of how our Excel calculated budget uses the two rates, one rate Oct-Dec and the higher rate Jan-Sep because we're looking at the financial year Oct-Sep but want to reflect the uplift in Jan. This then shows us being over budget for the first 3 months of the financial year in Power BI which is using the Sage 200 project accounting data, as it assumes they'd all be at the latest/current rate which is disappointing. Is there a way there could be valid from & valid to dates, similar to the way exchange rates are maintained for example? Thanks