Hi michelda,
I think the tolerance check is the last opportunity to confirm the correct ILS QDM is in the box (it's too late to do anything about it by this stage except GA - but I think the "logic" *1 is:
FCOM 1.22.30 P50:
ILS APP Mode Arming Conditions ... "The aircraft is above 400 feet RA," etc.
FCOM 1.22.30 P 53.
"Align sub-mode.
Align is a sub-mode of LAND also known as "decrab" that lines up the aircraft's axis with the ILS course at approximately 30 feet. It is not displayed to the crew."
On TriStars - it was quoted as being acceptable if ILS QDM was within 6 degs of Runway QDM - but I cannot find any Airbus equivalent limit published.
*1 = oxymoron.