Hi divinehover,
Your engines will be flat rated to ISA + ? (my old -22Bs were to ISA +15 degs C). So maximum thrust was always 1.526 EPR, & MCT was 1.419 up to 28 degs C at sea level (Simples?)
When it was less dense, the maximum EPRs reduced because we were now limited by another parameter usually Fan speed or TGT.
What could be simpler?
We used to Flex EPR down for reduced thrust take offs - but we knew our Max and MCT limits because we had to set them manually. You probably use FMS to control them now.
In the cruise we bugged up MCT from tables for the density altitude (in case it was needed), and expected cruise EPR using weight, density Altitude, cost index / Mach no. etc.
So for example I would like to know that at FL410 the thrust set is 77% of what that engine can produce under those conditions.
We had RPM limits which exceeded 100% as the engine was developed. So 77% of what? It's just a another number.
Is your TGT expressed as a % age of melting temperature?
Are your V speeds expressed as a ratio to V stall?