No. 4 Rifle; Zeroing Instructions Data Inconsistency?

[Rick]

As I'm once again getting ready to make our range my second home as the last of the snow disappears, I am again distracted by the zeroing data for the No. 4 rifle being inconsistent when looking at the Canadian pams versus the Brit/Aussie pams that I have on hand.

I know this is mostly academic at this point, as Mk VII ammunition has become pretty much as easy to find as unicorn poop. But to summarize what is aggravating me so much, the Canadian pam Shoot To Live from 1945 is my Canadian resource.

The later 1991 and 2002 Canadian pams for the rifle concerning operating instructions (curiously) have no references to zeroing instructions. (As well, I thought the Canadian military coming up with "Shoot To Live" as the appropriate title for training infantry to kill with the rifle was a product of modern Canadian governments).

Because all training centres have not the complete facilities for zeroing rifles
at 100 yards, the methods of zeroing have been made available for both the
30-yard and 100-yard targets, although the latter is better. In either one
if you aim precisely at the point of aim, the sights should cause the bullets to
strike the 30-yard target 2.25 inches above the auxiliary aiming mark's base
and if it were to continue to the 100-yard target it would strike 8.5 inches
above the auxiliary aiming mark's base.

Should it continue on to the 300-yard target in the distance, it should fall
directly upon the aiming point.

The Brit's Precis No. SA/19A from 1950:

In the case of Rifle No. 4 fitted with a Mk 2 Backsight, the apertures of which
are sighted for 300 and 600 yards, the Rifle will be zeroed using the 300 yard
yard aperture with a Bayonet fixed.

So: the wartime Canadian pam says the No. 4 rifle with a 300 yard aperture will have a POI +8.5" at 100 yards when zeroed. British pams say a No. 4 rifle with a 300 yard aperture will have a POI of +6.0" at 100 yards when zeroed.

+8.5" versus +6.0" at 100 yards - that's a HUGE difference. Doing some quick tests in a ballistic calculator shows that the zeroing information from the Brit pams is almost certainly correct, while there's no way the Canadian information can be correct.

Am I missing something here in what I see as such a huge discrepancy?

I would think Canadian infantry NCO's assigned to be SAIs at the battle schools, taking recruits through the process of zeroing their rifles would immediately realize that using this data to zero at 100 yards did not get the expected correct results when firing afterwards at 300 yards.

And is there a Canadian pam for the No. 4 rifle published after WWII that contains zeroing instructions that I'm not aware of?