It’s a highly technical area of share-based payments revolving around the allowability of expenses on an accruals basis as distinct from the taxman’s version of allowability. As I remember, the taxman will only allow as deductible the value charged to the expenses but limited (and here I can’t remember the limit!). Whatever the limit imposed by the local jurisdiction, it created a temporary timing difference which was then multiplied by the current tax rate to give the deferred tax amount.
I’m not sure that that helps a lot but if you feel the need to, post again and I’ll try too find the question again
Fortunately, the topic is not a frequent visitor to P2 so, on the balance of probabilities, it really is unlikely to appear in December …….