who 2 fixtures 'double' my par reading or is it not that simple?

[ExpensiveHobby]

I have a current Orbit LED light. My par meter is only showing 270 at the surface. I had hoped it was higher but Im not really surprised. I love all the features of the light and its multichannel programming just dont like the output. Would purchasing a second light of the same kind and running together actually increase the par values or just increase the spread?