I find myself oddly concurrent with Mrs. Glover on this point.
The reality is that the legislation unamended does not increase the post-tax earnings of the Governor General. This amendment would impose, not just a small pay cut, but a significant and punitive pay cut, which I don't think would be the intention of the legislation in the first case. It's important to reiterate that the increase is simply to reflect the fact that this legislation makes the Governor General's salary taxable.
I don't support the amendment, but I do support making his salary and the salaries of future governors general taxable in the interest of transparency.