The performance difference of "Solar position table" and "Incidence angle modifiers"

Dear Gentlemen,

On the Collector Geometry and Optical Performance page of SAM, there is significant difference for the calculation results of "Solar position table" and "Incidence angle modifiers".

When checked the "Incidence angle modifiers", all data in "Solar Position / Collector Incidence Angle Table" were suppressed and all values (that is, Const., C1, C2, C3, C4) of "Transverse incidence angle modifier" & "Longitudinal incidence angle modifier" in the "Incidence angle modifier coefficients" were made active. Although all the original data in the page remained unchanged, the performance difference is significant.

Could you please clarify us about the possible reason.

Regards,