Extrapolating coefficients from other power classes

I'm currently using the IEC61853 Single Diode Model in SAM to simulate solar systems, and I'm using laboratory test data from different manufacturers to calculate the coefficients, e.g. C1, C2, C3, Diode factor, etc. Some of the manufacturers I'm working with haven't done the IEC 61853 multi-irradiance testing on every power class, so they'll give me results for 320W panels when we'd also like to simulate 315W, and 325W panels from the same product line. Is there a good way to modify the coefficients I calculated from the lab test results for other power class modules that are slightly lower or higher?

Dear Michael,

I am not aware of a way to modify the coefficients to accomplish this.

Best regards,
Paul.