Casual gain calculation (CIBSE gain)

I am modelling a room which is 18m2, occupancy of 4.

The lighting gains are 12w/m^2,small power 25w/m^2, occupancy sensible gain 90w/person, occupancy latent 40w/person

My understanding is the casual gain is made up of sensible load from people, lighting and equipment

Therefore, the casual gain should be (12W/m^2*18)+(25W/m^2*18)+(90W*4)= 1026W

However, Hevacomp when using CIBSE gain gives me a casual load of 906W

There is a mismatch between my hand calculation and the Hevacomp result, could someone let me know how this Casual gain is calculated on Hevacomp

Thank you