Are there more tapes?

Macleans provides an interesting detail on the 'deniability' splice:

For example, the Liberals dispute a sentence in which Dosanjh hinted at Grewal being rewarded if he crossed the floor. The released transcript said: "No one can forget such gestures but they require a certain degree of deniability."But the Liberals say the word "deniability" was spliced into the sentence from another conversation not released by Grewal.

Given that one should, with the right technology, search for a digital sound within the released tapes, this last point is very important. It means that there are more tapes.