In Australia we had adopted the same procedure which was approved by our Aviation authorities.
I never had to do it myself as I already had enough hours but as long as you can justify the correction (and highlight it to them), I am sure Cathay won't mind.
Keep in mind Cathay has probably the highest percentage of pilot's with a military background than any other airline, I think you won't be the first to correct your logbook.
In Australia we only added .1 though
Gliderboy
ps Oh and I DON'T work for Cathay (just yet)