A (50/60 Hz) Transformer. Which one will give more Output?

Suppose a Transformer has some rating on its nameplate such as:
THE RESULT IS SHOWN BELOW:

KVA= 100KVA, 
R =  500ohm
L= 1.5henry
Frequency = 50Hz

XL = 2πfL = 2 x 3.1415 x 50 x 1.5 = 471.2ohm

Impedance Z = √ (R2+XL2) = √ (5002+ 471.22) = 687 Ω

Power factor, Cos θ = R/Z, = (500/687), = 0.73 lagging,

Transformer output in active power, KW = KVA*cosθ

= 73KW

now again, taking the frequency as

 f= 60Hz,

XL = 2πfL = 2 x 3.1415 x 60 x 1.5 = 565.5Ω.

Impedance Z = √ (R2+XL2) = √ (5002+ 565.52) = 754.8  Ω

Power factor, Cos θ = R/Z, = (500/754.8), = 0.66 lagging,

Transformer output in active power, KW = KVA*cosθ

= 66KW

Difference in kW= 73-66 = 7KW= 

So the lower the frequency the higher the output..

Reason is the inductive reactance.