Drop in P.F & Error in Power Calculation

How to reduce error in power calculation (Induction motor) due to change of Power Factor?

what is the reason in this case of P.F drop?

Here I am giving comparison of both types of measurement from

1. Energy Meter
2. Theoritcal Calculation of Power by Getting valu from C.T

At the time of measurement Load was 81 % (from C.T)

Compressor Motor: 250 KW, 400 V, 50 Hz, D, 440 A, P.F 0.86

1.Power Calculation from Energy meter:

Voltage = 392 V
Current = 346 A
P.Factor= 0.824
Power = 194.1 KW


2.From CT value in MCC (Simocode):

According to C.T, current is 356.4 A (81 %)

Voltage = 392 V
Current = 369.6 A
P.Factor= 0.86 (Taking NamePlate P.F = 0.86 )
Power = 208.1 kW

Error in both reading is 6.72 %

The Substation have 7 no of compressors each having 250 KW induction motor.In the Substation Capacitor bank Controller (BK-12) shows power factor of 0.95. We Put energy meter in MCC at the output of magnetic contactor. There Power Factor according to that meter was 0.824.

Motors have Loads in the range of 80-90 %. Other Loads are Lighting & Heating elements.

The question I want to ask that why power factor drop down to 0.824 as motor power factor is 0.86?