It depends on the controller on the SSD.

If you've got a "normal" SSD controller w/o compression then you can run any compression ratio you like.
There might be a very small performance penalty as generating random data can have a tiny impact on the score but in general the scores should be very close if not identical.

If you are running an SSD that utilizes compression (SandForce based) then you should go by 46% or more for the most realistic/true-to-life scores.
(it really depends a lot on your data)