CRA is considering whether a GST/HST waiver can be restricted to a specific issue

ETA s. 298(7) provides that a person may waive the application of the time limits for being assessed in respect of a “matter” specified in a waiver made by it. CRA is mulling over whether, in the context, for example, of a CRA audit of taxable and exempt supplies made by a registered supplier, it should take the position that, since any assessment made by it would be only for the registrant’s global net tax number, therefore it would not be permissible for the supplier to limit a waiver to whether a particular supply was exempt or taxable – instead, the “matter” at issue must be regarded as the entire net tax calculation for the reporting period.

A similar spurious issue could be (but has not so far been) raised on the income tax side, given that a Part I tax assessment is for a single Part I tax number.

Neal Armstrong. Summary of 27 February 2020 CBA Roundtable, Q.14 under ETA s. 298(7).