Steve. This is the Hong Kong Civil Service we're talking about.
You know, brown envelopes left over from the second World War, everything in triplicate - I bet we still have carbon paper somewhere, letters that address you as "yourgoodself", office staff chastised for catching the 17:20 bus because they are paid til 17:23, a class structure that Victorian England would have been proud of, wetting of pants by the 4th floor whenever the word "Bureau" is mentioned, penny pinching in the extreme but pound foolish when it comes to most things.
What is laughable is to see their attempt to relate shift-working controllers' rosters and entitlements to the 150 year old Civil Service Regulations. Written clearly for the job of a pen pusher in the British Army in the 1800's, these archaic tomes never envisaged civil servants not working 9 to 5, 5.5 days a week, without anyone needing to cover your postion if you were sick or on leave. (sickness is probably forbidden in there somewhere!)
So we have this ridiculous system of relationship to office workers in Admiralty, who gleefully have their weekends and public holidays off, while frontline supervisors struggle with rosters full of holes. Daily manning sheets littered with "Not manned" in critical poisitions make a mockery of the roster.
There is no such thing as callout or reserve to cover sickness or leave- well there is, but they have no mechanism to pay you for it.
So, as you say, they conveniently have the ironically named TOIL as their secret weapon.
TOIL is like their version of Monopoly money - they can throw it around at a whim without upsetting the taxpayer. Any time they need you to work overtime, or come in on days off for training etc, they say "oh, but we'll give you TOIL". It's their great piggy bank of IOUs that never get paid back because the don't have the staff . And the reason they don't have the staff is they just do not understand why anyone would want to have their leave - don't you want to save it up for the next 30 years and retire early??? Great!!
Disjointed rant over. Can't be bothered any more.