Incorrect gain of AD835 as a Voltage Controlled Amplifier

Hi all
I configured a AD835 as a voltage controlled amplifer which was same to its datasheet (attached file).

My test condition:
Schemes: same to Fig.21
Vin (pin Y1): 100 mVpp, f = 10MHz
Vg (pin X1): 0.5VDC
Output signal was measured at pin 5 (pin W) by an oscilloscope.

Measurement results:
Output signal = 380mVpp

So, it indicates that gain should be Vout/vin = 380/100 = 3.8.

However, in its datasheet, this value should be 2.

I am very confused by this.

Does anyone, have experience with AD835, help me to clear this problem ?

thanks in advanced