Software/Script for calculating remuneration: converted from old system

We need someone to write an app/script/XLS sheet to help us convert our old remuneration calculation system to one that matches the new CMS that we are going to implement. In the old system the operator had 3 ranges of efficiency (0 to 30 000 units, 30 001 to 45 000 units and 45 001 to 60 000 units) and was assessed for quality (either 0 or 1: quality goal met or quality goal not met). Each range of efficiency had 2 rates: 0 - 30 000 = x OR x+1 (x selected if quality goal not met, x+1 selected if quality goal met) 30 001 - 45 000 = x+2 OR x+3 (x+2 selected if quality goal not met, x+3 selected if quality goal met) 45 001 - 60 000 = x+3 OR x+4 (x+3 selected if quality goal not met, x+4 selected if quality goal met) So remuneration for a person who met their quality goal and completed 43 000 units would be: [30 000 x (x+1)] + [(43 000 - 30 000) x (x+3)] I can provide more examples and explanations if needed. Numbers above are for illustrative purposes only, to facilitate any calculations. The new CMS does not allow a division into efficiency ranges - it requires one rate X to be input into the system, which is then multiplied by the total number of units produced (no ranges here). It only allows a percentage to be added to the amount at the end. We need to find a way to arrive at a similar remuneration (+/- 1-2%) in the new system with the new variables.