What is the test for just and equitable granting of an extension?

... Counsel for the Respondent argued that the requirement that the granting of an extension be just and equitable in the circumstances was a separate test that must be met as a condition to granting the application. Such condition does appear in subsection 167(5) as a separate test. But the condition is derived from the reasons for and circumstances of the request. The reasons and circumstances here do not give rise to any asserted injustice. There has been no assertion here of foul play, dishonesty or prejudice. I can find no cases, nor has the Respondent's counsel offered any cases, that would support the contention or give an illustration of a situation where all the other conditions for the granting of the application are met and it is still found not just and equitable to grant the application. The reassessment is not adversely affected by granting the application except that the reassessment can then be dealt with on its merits. In these circumstances it strikes me as inequitable not to apply the principle set down in Seater v. R., [1997] 1 C.T.C. 2204. ...