In that case, whoever told you that you needed one must have had one for sale.
I have disabled the SAI on mine with block off plates, but it was a matter of choice, not need.
Since your bike is in the shop and the tech thinks the decel burbles are excessive, you might want to ask him to check which tune is loaded? An aftermarket pipe with the stock tune will burble excessively. The TOR tune reduces the burbles to the normal level.